I'm unbelievably honored by your nice words about my puzzle! The origin of the puzzle name indeed comes from "chess sudoku", but it's more unfamiliarity than uncomfortableness: A friend of mine asked for a chess sudoku and I wasn't aware of that expression for an anti-knight sudoku (the name under which I knew this puzzle type up to that point), so I wanted to try something more unique and came up with this idea :) And yes, you got the main idea of the puzzle exactly right ;) Thank you a lot for featuring this puzzle on your channel!
I never comment on videos at all, but this puzzle was sublime. I'm genuinely baffled as to how this was created; I like to think I'd set up an actual chess board and work from there but I genuinely have no idea. Thanks for your time and effort with this, loved it.
I decided to do this puzzle because I really like Chess sudokus and this was subliminal I absolutely loved it a lot of the deduction it was so good it was so fun
another way to think of it: the "top" player has made 14 moves while the "bottom" player has only made 12 moves if the knight is stationary, so it *must* have moved!
Normally I am just watching these with slack jawed awe and never have any moments of seeing things Simon missed but something about the combination of rules hit my brain just right and there was a lot of times I found myself desperately waiting for Simon to notice what I had seen.
I had the same thing happen (for the first time watching his videos) and I think it had something to do with the amount of information that was presented. It's really easy to get distracted with a puzzle like this!
The most original puzzle I have ever seen on this channel, and that’s against a lot of competition. Brilliant Christian, thank you. Nice solve Simon, as always 😊
The Schrödinger's cell puzzle, is the one I still want to re-watch. I just was really glad to see something quirky, that was a reference to the channel's quirks. There was one, where it was almost entirely cages except like 2-3 spaces, and every single cage had like the sums 3-30 or something like that, all of the sums, thought that was cool, but yes, the unique-ness here is pretty unparalleled, this would definitely be top 5 if not top 3 and I'm only 20 minutes into it.
Yes, chess players do have an advantage in this puzzle. For instance, the second we know that Bg5 and d3 were the moves, we know that the bishop from f1 can't go left, because pawns from d2 and e2 can't both let them go (because of the move order). Also, experienced chess players think about the queen on h4 giving a check immediately, even without thinking. Totally enjoyed solving this puzzle several months ago! And glad to see how it's much easier to solve with the multi-color line tool.
Absolutely! Simon is usually much better at these puzzles than I am, so watching him repeatedly trying to castle his queen through his rook was pure catharsis!
@@aous9679 no-one knows in advance which puzzles will be featured. But most of the setters (especially in the CTC community) publish their puzzles to the site called "Logic Masters Germany" ("Rätselportal" in German). Note: when you open the first link that you find in Google search, you may think that you opened the wrong site because it looks like it was created in 1990 by a scholar. No, that's the right one.
The logic that resolved the white king's position involving the order of the pieces... I am in awe! Brilliant deductions by Simon and brilliant setting by Chris!
@@thecaneater Just because it also solves without that logic doesn't mean it is a lucky guess. The rules state that there is a game of chess being played. Chess follows rules and using that knowledge still results in logical conclusions, not just guesses...
Not fully sure if I'm correct, but in order to conclude the king moves to e2, you need pawn e2-e3. But this blocks this bishop c1- f5. So if the bishop comes first, that means the black Queen is already there, so the king never escapes the check and the moves are always illegal...?
Oh no their queen! It's really fun and congrats to Simon for solving it in movie time, definitely a hard one if one's chess skills are rusty :) There were a few extra interesting things that were missed: 15:40 move Bg5 (5) has to come after d3 (5) but before the e pawn (2) moves (if it does at all) because it can only go to e3, which means the white lightsquare bishop on f1 never gets the chance to move on the f1-a6 diagonal further than e2 already, and when later g2 pawn (7) is determined to stay still we know the bishop (4) stays in box 8. 1:04:00 some unusual deductions, but not unlike any other variant - the knight on g1 (8) can now only end up on g1 or f3, any cell seeing those two squares cannot be 8, namely r5c7 and r6c7. 1:23:35 16-3=15??
I think there was ("as useful as a") "chocolate tea-pot" in there as well. Not sure if you have that in the filter yet, but it's a recurring Simonism (Simon Says?) that paints a clear picture for me.
I do believe that this should be the start of a whole new Sudoku kategory. I could never do this myself but watching it was so incredibly fun! And maybe if more people would do puzzles like this, Sven could Upgrade the App to make it easier :D
I am afraid of Phistomefel getting his hands on this puzzle and adding his Phistomefel rings on a fully chess boarded Sudoku. If Christian and Phistomefel were to work together....
When I first solved this puzzle many months ago I had to use two different grids and a chess board. One grid for Sudoku. One grid to mark which pieces stay put or have to move and the chess board to keep track of the moves. It's absolutely amazing Simon could do this all in one grid.
I did the puzzle without lines, just by colouring the pieces that had moved. Because of that I wasn't able to disambiguate the final 46-pairs as I didn't remember that it was the pawn that was occupying the 6 in box 4 :D
The ordering of the moves was actually quite restricted. In particular these moves have to occur in this relative order: ...e5 ...Qh4 Bg5 e3 Ke2 f4 ...Bg4 & Nf3 ...f5 ...Nf6 & ...Kf7 ...Rc8 Which spans 10 out of 13 of black's turns
This is exactly what i also attempted to do after watching the puzzle.. I was wondering if this is how someone good at chess would attempt to solve it too (instead of looking first at sudoku constraints)
So normally the software simplifies the process of solving puzzles, but this magnificent puzzle is just much more accessible using actual pieces of chess.
I could definitely see that making it easier to understand what's going on. Realizing the black queen would be putting the white king in check, for example, would be much clearer if the queen weren't represented by a 3 that's connected to a queen by a line.
I'm still at under an hour into the watch and so far have made 3 deductions. 1. This is a beautiful but very convoluted puzzle! 2. I was 💯 percent correct in seeing the solve time and deciding to just watch you rather than attempt myself! 3. (Though this one I already knew) you are INCREDIBLE!
Simon, I love the long videos. This , for me, was the greatest of them all. The final force of the Knight move was just amazing. A whole new level of genius. Koenig, you are a master. Well done.
Yes, as someone who plays chess since the age of 6, i just had mental images in my head where each chess piece stays once i placed it at its final destination. For example it helped me see the 3 in r7c3 directly without even thinking about it.
Another reason why the knight in r8c7 had to move was that the bishop in r5c7 was giving check to the white king in r7c5 and this could not have been the most recent move, because the black pawn in column 6 moved after the black bishop. So the knight had to block the check.
72:47 Was so confused at the start because the only way I could see the black rook escaping box 2 (because the king was blocked from column 4 by the 3 pawn) was to go forward, but that would push the 5 pawn into box 4 as well which broke the white 5 bishop, which had to go to box 4 because the white 5 pawns took up boxes 5, 7, and 8. Was a eureka moment when I realized the rook could just go sideways, also proving that all the king side black pieces moved My favorite logic was when the white bishop blocked the black queen's path to her deduced spot, which meant it had been moved after the queen, proving that the king wasn't in check So many great moments like this. Loved this puzzle
I love that the final ambiguity about the knight moving isn’t necessary to solve to get the sudoku to mark as solved, but is necessary to fit the rules of chess. A wonderful mini-puzzle that acts as a fitting coda to a magnificent larger one.
To add on the "black has moved 13 times so white have to have moved at least 13 times too", the knight needs to have moved to block the check on the white king by the g4 (r5c7) black bishop, as we know that bishop move is not the last move played, since black still has rook to c8 to play after that bishop move, so the check on the white king must be prevented in some way, and that is the only one that works.
@@Jivvi Kinda depends on the order you make your deductions, knowing how many white pieces have moved can help solving some of the black spawn stuff. But yeah you don't need it for the solve.
@@danielyuan9862 it's not a solve condition though, and there isn't even a way to enter it into the puzzle. It implies that knowing the exact position is necessary to solve the sudoku, but as he discovered, it actually isn't.
As some already commented, the knight has moved, for the same reason that you deliberated if the black Queen was checking the white King. Lovely puzzle. Well done Christian for constructing and Simon for solving.
My notation was all highlighting: purple for pieces that didn't move, grey for where pieces used to be, and green for their new locations. I did spend a lot of time looking back and forth to see which greys and greens went together, but I think the reduced visual clutter compared to lines worked well for me.
I used green for pieces which I knew were moving, grey for not moving, and purple once I'd written the digit into the grid corresponding to where they moved to. I found I was able to keep track of who'd moved where from memory (and because only so many moves are legal)
As a chess Master I've got to say that I absolutely loved this puzzle! This is the perfect example of a chess sudoku. I especially liked the final touch of the knight having to move from g1 to f3 in order to block the check (and fit the move count). I can't imagine how someone can come up with something like this, but thanks a lot for taking the time to build it! Brilliant!!
One could determine the position of the King-side bishop earlier! Since the queen side bishop has moved, it means the queen pawn has advanced one step forward. This restricts the king-side bishop to two places, one of which is occupied by the king. Hence, it must have stayed in place.
1:06:00 you can deduce that the 8 is C6R6 if 8 is in either positions in C7 in box 6 the knight couldn’t stay where it is because there would be two 8’s in column 7 so it would need to move to the only other position C6R6 which would place a second 8 in box 6 so the 8 in box 6 isn’t in column 7 so it’s in C6R6
Illegal moves didn't come to my mind when solving this, but it's incredible that they managed to be relevant. Christian take a bow! This is truly a one-of-a-kind puzzle! Sidenote: other than move count, the knight must move to f3 (r6c6) to block the attack from the bishop to the king Edit: I'm currently getting sidetracked with the question: "Through how many differnet move orders can you achieve this position?" Stick around here for who knows how long to find out the answer. And the answer is 43,710,624. That didn't take as long as I had expected.
You know, I finished this puzzle but thought the knight moving/not moving was unresolved by the final solution. Thank you for pointing out the blocked checked before I came down here and made a fool out of myself. lol
It has to move to block the check, but if it's the last move then we can't say whether or not it actually *did*. The snapshot that we're seeing could be from just before that happened.
IMPECCABLE. Two of the best sudokus of all time in a row. Just astonishing. Love the novelty of this ruleset, so many beautiful deductions, and brilliantly solved Simon, the fact that you’re well-versed enough in chess to get those parts is just awesome!!! PS: the 3 in the corner didn’t get its song! Oh also beautiful guitar playing as usual!
I'd love to see that. Simon is so good at spatial perception -- but Mark has more of the competitive killer instinct, I think, and would probably pull out some improbable brilliant sacrifice to win the game.
I was away from home and could not watch this when it was first posted, so I watched it tonight. Guitar intro and outro - lovely. Thank you for that, Simon. And the puzzle and solve - my goodness, I could totally follow what you were doing, but there is no way I could ever do this, even understanding and, probably ,watching the video. You are really amazing when these complex logical phenomena are presented. Thank you so much!
this has got to be one of the best setting of a suduko ever.....completion and perfect follow through on an idea. Almost a shame there wasn't a chessboard at the end, with the end position displayed
Awesome puzzle! I loaded final position into a lichess study and found some interesting things. 1. The knight must be on f3! - If the knight had stayed on g1, Black's bishop on g5 would have the White king in check, but also somehow be nestled in front of the pawn chain -- this position is impossible to achieve with normal play. 2. The position is completely winning for White -- but oddly close to drawn! Obviously, if play resumes normally from this position, White is completely winning because the black queen hangs on h4. However, if it were Black to play in this same position, the position becomes unclear after bxc4, counterattacking White's queen.
I've recreated the match, it's white's turn. But frankly, that's not a possible match at all, the moves are absurd (well the condition was that each piece only moves once so it's not unexpected)
That was 'out of the ball park' one of the best sudoku puzzles I ever solved. The way the sudoku rules interact with the chess rules is amazing. Instant classic!
Don't play chess or sudoku and generally just watch this channel since I find your voice soothing but somehow this puzzle just clicked for me and was able to do it super fast just in my head... Got me excited since I'm usually totally lost trying to follow your logic even with you thoroughly explaining it every time
This is my first try on any non-classic sudoku. Got pretty far in 20min and was sure I could solve this before simon. But then I spent 80+ min wandering what on earth can I do next? Finally I gave up and came to watch the video. I don't think I could've figured out that illegal pawn move for king's check in a million years although I play average chess. The puzzle is absolutely mindblowing. Hats off to Chris.
This puzzle was fantastic, but I have to say it was made way harder by the software not letting me hide the chess pieces and numbers to see my pencil marks. It's hard to read a 5 superimposed on an 8... Absolutely brilliant puzzle design, though, bravo!
Pure logic pawn! Jokes aside, I've had this thought on multiple occasions: A small text box in each cell would be nice in order to comparatively/sequentially number cells or write shorthand descriptions to clarify while solving. Also enable highlighting for this feature and for both corner and centre pencil marks and full colour palettes for the highlighting.
1:03:29 finish. As a lapsed chess player, I thoroughly enjoyed this. I didn't even consider having to worry about the king being in check, until I got stuck and sat staring at the screen. This puzzle is so unique, I don't even see how it could be duplicated. Amazing!
1:00:05 ... I haven't printed out a completed puzzle in some time, but I just had to with this one. Absolutely mind-blowing; if not the 'greatest' sudoku variant of all time, it has to at least be in the conversation! Extraordinary! (I actually counted moves as well to locate the White King's Knight; I overlooked the check-blocking.)
solved in 40:56 - incredible idea with the chess and all. I was trying to disambiguate between ke2/f2 and ke7/f7 for a long time, then realized qh4 couldn't be black's last move, which rules out kf2. super cool
I don't really know how to play chess but Simon's explaination and hypothecation are so comprehensive that he indicates all the possible moves that special piece therefore letting me understood the rules of chess in the process of Simon solving.
Didn't solve this on my own, but a short while into the video I thought I saw something clever, opened it up myself, and started solving it along with you. I'd NEVER claim that counts as solving, because I was standing on simon's giant shoulders, but it was a GLORIOUS experience, - and even if I was stealing simon's insights, I got a lot of my own insights too. I had the EXACT same moment of horror with the deadly pattern at the end... and had the exact same ECSTATIC EPIPHANY at realising the bishop disambiguated it. GLORIOUS puzzle, wonderful video. I should have spent the last hour writing, whoops! Thank you again!
Memeristor is interviewing phistomefel Tuesday at 11 am, 12 pm your time my friend. Thought you would like to know, in case you didn't. Play chess casually with a friend and my dad. This puzzle was phenomenal.
@@longwaytotipperary check above. I linked you to his you tube channel. Let me know if works. Can subscribe to it and set a notification. Not sure if going to see him or not yet.
I never normally try the puzzles on this long a video. The concept was so intriguing that I had to give it a go though. I had to get a hint from the video about considering checks but solved it in 108:11. I'm now exhausted and may have to go back to bed!
My solution for this looked like a disco nightmare with all the colour-marks and lines I was drawing. I also needed to peek at the video to work out what to do with the top-right Rook when I got stuck, but after another roadblock with the mess of threes and forgetting that kings can move diagonally, I got it! Impressed with how clean your solution looks.
1:03:00 I found this logic really impressive, recognizing that the "king" must have moved already to make the "pawn" move legal. Spotting an imaginary pin in an imaginary game of chess in a Sudoku is just fabulous!
Loved watching the solve. I couldn't help but think that highlighting the pieces that need to move in green and and the pieces that stay still in red might have helped a lot to see which pieces you hadn't looked at yet and whether they needed to move or not. You could even highlight the square they move to in a different/same colour to help with the visualisation. Thanks for the lovely long video!
Genial Christian, ein unglaublich schön konstruiertes Puzzle!! Und Simon, wieder einmal ein beeindruckender Lösungsweg. Ich brauchte 3 Stunden für dieses Meisterwerk!
This was an amazing ride. When it dawned on me, that not just moves, but also the resolving position determined the placement of pieces, I finished quickly, but with my jaw dropped, in total amazement. Now I am waiting for a Go-Minesweeper-Sudoku hybrid…
When trying to figure out where the Queen goes around 34 minutes in, I was screaming at my screen because Simon failed to realize you can't put the queen through the rook, locking the 3 of the Queen to the 2nd column. I'm not sure how much of an impact it has on the puzzle but it hurts to watch. Bobbins!
I am a decent chess player and have some experience in solving proof games. So, a few points: 1. This is a brilliant puzzle 2. See 1. 3. How the f do you set this 4. Probably the puzzle is not suitable for most of the channels audience. 5. Probably the puzzle is not suitable for being solved in CTC Software 6. See 1. I am amazed, congrats to Christian for an absolute masterpiece! The disambiguation whether the g1 Knight moved or not is the climax... And yes, some chess knowledge does definitely help. A lot of deductions, involving pieces switching place for example, came (more) naturally to me.
Another possibly interesting puzzle would be finding a legal series of moves to end up in the final position. There's enough dependencies it doesn't seem trivial (e.g. the white dark squared bishop must've moved before the e and f pawns, but after the d pawn).
I was in the exact same situation. I found two different, seemingly viable solutions, but as soon as I realised I had to bear 'check' in mind, it resolved my fork.
A useful way to pencil mark in order to be able to "read" the board was a colour for each type of piece, used for the square it landed, or was confirmed to have stayed (together with line tool in same colour). I used Blue for Bishop, greeN for kNight, Red for Rook etc. Also marked confirmed empty squares in pale grey making it much clearer which pieces needed further consideration. Now if only I'd spotted all the other stuff as fast as Simon....
I finally tried one as I felt this was the first time I got off to a quicker start than Simon.. I got really far but then I had to go back to the video to cheat a bit and I noticed.. I forgot the king was in check at some point. After that my puzzle fell like a house of cards so it was the final piece I needed. Still, this was a very entertaining puzzle!
To answer the question from 38:32, as a chess player, I definitely think that helped me to think through this puzzle. In watching your solve, I consistently came up with concepts like restricted digits a lot faster than you did, which I think is down to my chess experience. That said... I did try the puzzle on my own before watching and didn't get very far, as the sudoku part of my brain is not nearly as well honed as the chess part. I'm pretty sure I could have gotten there eventually, but I reached a point, after about 45 minutes with only some 5's in the grid and some knowledge that 3 was restricted, when I decided I'd rather watch a pro do it. I think that sudoku experience is more important to solving this puzzle than chess experience, but I think that chess experience definitely helps. In other words, an experienced chess player with a casual knowledge of sudoku (me) would have taken hours to solve this, an experienced sudoku solver with a casual knowledge of chess (Simon) would have a much easier time, and an individual with experience in both would have an even easier time. This was a really fantastic puzzle, and even though I couldn't solve it myself I really enjoyed it.
Simon, there is ANOTHER way to know whether the knight on g1 moved. Can you see it? Black played Bg4! If white did not play Nf3 beforehand, Ke2 would have been illegal. (this is way cooler than counting moves IMO)
While playing with the puzzle, I discovered a second solution only if you allow the king to be in check. That one rule creates a single solution puzzle. Oddly if you had ignored that point and put the king in check, you would also have found a second solution for the sudoku part of the puzzle.
Tried to do it on my own but I just couldn't get past the the first few fives and ones, so I followed along and with every hint of yours stopped the video and tried it on my own again. I actually got the hang of it after some time yet it still took me 92 min to finish. This was tough, wow! Also to Chris, just wow!
I think this is the first puzzle I solved faster than Simon (it took me just under 54 minutes). As a relatively advanced chess player (1900 USCF), I think I had a slight advantage with solving this puzzle, but not necessarily a large advantage. The main things were very quickly recognizing all possible moves for each piece as well as possible checks.
At the end, Nf3 is required, else the white King is in check from the bishop on g4. Wowzer what a puzzle. Absolutely loved the fact that you needed to play out a part of the game to resolve the white King. I'd consider that the "breakin"... and a delayed breakin that's 3/4 through a puzzle ?!?!? I've never seen that before.
I would have used a color for each piece type, probably easier than whatever simon ended up doing, looked hard to parse to me. May give myself time to forget the solve and give it a go, but was intimidated by Simon's solve time.
Great puzzle. I was stuck for so long, then decided to watch the video. When you talked about how the white couldn't put itself in chess when pushing the pawn, my mind was blown and suddenly all the last pieces fell into place.
From an abstract view, the mechanic of being given a digit that fits along a line is very interesting. Made for a lot of interesting thought paths. So many markings used to keep track of things since it was so hard to read the numbers overlapping any pieces made for possibly my busiest grid in the end.
An excellent puzzle indeed. I love that you figured out the knight at the end a different way than I did. My logic was that white would be in check at the end if the knight didn't move which would be fine except that black has to move a rook after moving that bishop.
Finally, after 3 days, and 3 restarts of this puzzle, I can finally watch this video. As a someone who loves chess I've never been so determined to solve one of these puzzles for myself first. This was a fantastic puzzle.
Nice puzzle, but it's incredibly confusing. Here's a couple of generalised suggestions for the interface which might have made the puzzle easier to solve: a) The ability to default corner pencil marks to the top right corner of a cell b) The ability to delete elements from the puzzle setup after the solve has begin
I made surprisingly good progress here, but after minute 67 I noticed that I couldn't put a 5 in box 8 anymore (all not filled cells had a 5 looking at them). Must have been some mistake somewhere. I restarted, and the second time it took me 109:27. (At the end I was stuck for a while, until I looked at who is attacking what, which resolved the positions of the white king, and from there the rest followed.) For notation: I picked different colors for the individual pieces (dark gray for pawns, red for rooks, orange for knights, yellow for bishops, purple for queen, green for kings - I omitted blue on the second try because that made the pencil marks and final digits harder to read). Then I used the pen tool to mark the origin spaces with circles (if the piece could still be there) or crosses (if I knew it had to move away) of the same color, and used the cell fill color tool to indicate the location where a piece moved to (or stayed) (with partial coloring if there were multiple options). Due to the "one move only" rule that was mostly unique (just the rooks could possibly see each other, but that still was not a problem). In some cases I also used the lines of the pen tool to mark the moves of the bishops and queens (but removed that as soon as I got a position, as it would be too cluttered). I'll watch Simon solve this tomorrow.
at about 1:05:00 you could've deduced that the bishop could not move because of the order in which the other pieces moved. there wasn't a moment where the bishop was free to move, since the king only moved out of the way after the pawn on d2 blocked its diagonal to free the other bishop, which moved before the king
Wow, what a puzzle! Took me 150 minutes. I used traffic light color coding: pieces that move are green, pieces that don’t move are red. This helped me realize “I’m going to need to move at least two more white pieces” after finding that sweeping black rook move. It also resolved the final “did this knight move or not?” question. Yes it did, because otherwise black moved more pieces than white did, and that’s not allowed I also did reverse thermo markings: lines to show a piece that moves, just like you, but a circle where it ends to distinguish where one piece follows another.
I had a great time solving this puzzle (56min 3sec), but after recreating the position with chess pieces, I've come to the conclusion that neither player knows how to play chess very well. Black's queen and bishop are both being attacked, and based on the position, must have been for several moves. Not sure why both players decided to go with somewhat of a "bongcloud" opening (If you're not familiar with chess, look it up). White has a terrible bishop on f1, and I'm not sure why you would ever move the rook to h2 (but funnily enough is actually pretty well placed as taking the bishop on g4 will come with a discovered attack on the queen, while defended by the knight, assuming black has the next move and will finally notice their queen under attack). Neither player seems to have a concept of where to place their rooks, based on which files will open up (besides rook on h2). Stockfish (chess engine) determines that white has a +13.6 advantage, which is pretty crazy considering not a single piece has come off the board yet. Shows how absolutely terribly black has played, even though white is not much more skilled.
If anyone is curious, the browser stockfish on Lichess has white up +11 in this position (mostly because the bishop on g5 or sudoku r4c7 takes the black queen basically for free)
1:06:02 That 8 had to move to R6C6 because If the Knight Moved its the only space it could move to If the Knight didn't move the original square would be 8 which would eliminate the other 2 C6 by sudoku
50:40 Because white's D and E pawns are both restricted to the 2nd and 3rd rank, it is not possible for both bishops to move though that 2x2 box, as the C bishop needs the pawns to be at D2 and E3 while the F bishop needs the pawn to be at D3 and E2. These two combinations cannot exist within the same game. From that the F Bishops cannot move through the box as the C Bishop has already done it.
Truly a brilliant puzzle! This was the first CTC feature where I watched the first few moments, then IMMEDIATELY went to solve the puzzle myself, and then returned to watch the rest of the video! :)
I'm unbelievably honored by your nice words about my puzzle! The origin of the puzzle name indeed comes from "chess sudoku", but it's more unfamiliarity than uncomfortableness: A friend of mine asked for a chess sudoku and I wasn't aware of that expression for an anti-knight sudoku (the name under which I knew this puzzle type up to that point), so I wanted to try something more unique and came up with this idea :)
And yes, you got the main idea of the puzzle exactly right ;)
Thank you a lot for featuring this puzzle on your channel!
Terrific puzzle - amazing setting
I'm super thrilled this puzzle was featured. Since it's one of my all time favourites ✨️
I never comment on videos at all, but this puzzle was sublime. I'm genuinely baffled as to how this was created; I like to think I'd set up an actual chess board and work from there but I genuinely have no idea. Thanks for your time and effort with this, loved it.
Was there particular opening to set up the board?
I decided to do this puzzle because I really like Chess sudokus and this was subliminal I absolutely loved it a lot of the deduction it was so good it was so fun
1:23:48 I love how Simon does the most complicated sudoku logic, only to stumble at 16-3=15 at the end 😄
All we need know is a 9 x 9 chess game into a more conventional suduko grid
( shall we have one more pawn and the Kings Mistress ?
@@highpath4776 Shogi is uses a 9x9 board, so you could do it with shogi instead of chess
@@highpath4776 I've seen a variant with two queens, but the knight and bishop were swapped on one side, because you need bishops on opposite colours.
At the end of the puzzle the Knight on g1 has to move to f3 to block the the bishop on g4 checking the king on e2. Brilliant!!
Thanks for explaining that fairly clearly. Take a bow!
With Sudoku notation: At the end of the puzzle the Knight on R8C7 has to move to R6C6 to block the the bishop on R5C7 checking the king on R7C5. :D
Correct :-)
another way to think of it: the "top" player has made 14 moves while the "bottom" player has only made 12 moves if the knight is stationary, so it *must* have moved!
This is the answer because the rules state it’s “in the middle of a game” and if the Knights isn’t on g1 then it’s checkmate
Normally I am just watching these with slack jawed awe and never have any moments of seeing things Simon missed but something about the combination of rules hit my brain just right and there was a lot of times I found myself desperately waiting for Simon to notice what I had seen.
The 1s were so frustrating!!! They could've been disambiguated so early into the solve and he's just ignoring sudoku logic haha
The 3 in box 4 , the one in box2 and the obvious pawn moves in box 5 😬😬😬
I had the same thing happen (for the first time watching his videos) and I think it had something to do with the amount of information that was presented. It's really easy to get distracted with a puzzle like this!
The most original puzzle I have ever seen on this channel, and that’s against a lot of competition. Brilliant Christian, thank you. Nice solve Simon, as always 😊
The Schrödinger's cell puzzle, is the one I still want to re-watch. I just was really glad to see something quirky, that was a reference to the channel's quirks. There was one, where it was almost entirely cages except like 2-3 spaces, and every single cage had like the sums 3-30 or something like that, all of the sums, thought that was cool, but yes, the unique-ness here is pretty unparalleled, this would definitely be top 5 if not top 3 and I'm only 20 minutes into it.
Yes, chess players do have an advantage in this puzzle. For instance, the second we know that Bg5 and d3 were the moves, we know that the bishop from f1 can't go left, because pawns from d2 and e2 can't both let them go (because of the move order).
Also, experienced chess players think about the queen on h4 giving a check immediately, even without thinking.
Totally enjoyed solving this puzzle several months ago! And glad to see how it's much easier to solve with the multi-color line tool.
Absolutely! Simon is usually much better at these puzzles than I am, so watching him repeatedly trying to castle his queen through his rook was pure catharsis!
Where/how can i find these puzzles before they are featured into ctc?
@@aous9679 no-one knows in advance which puzzles will be featured. But most of the setters (especially in the CTC community) publish their puzzles to the site called "Logic Masters Germany" ("Rätselportal" in German).
Note: when you open the first link that you find in Google search, you may think that you opened the wrong site because it looks like it was created in 1990 by a scholar. No, that's the right one.
The logic that resolved the white king's position involving the order of the pieces... I am in awe! Brilliant deductions by Simon and brilliant setting by Chris!
His "logic" just turned out to be a lucky guess. The puzzle is solved without that leap in logic. I solved it without that convolution.
@@thecaneater Just because it also solves without that logic doesn't mean it is a lucky guess. The rules state that there is a game of chess being played. Chess follows rules and using that knowledge still results in logical conclusions, not just guesses...
Not fully sure if I'm correct, but in order to conclude the king moves to e2, you need pawn e2-e3. But this blocks this bishop c1- f5. So if the bishop comes first, that means the black Queen is already there, so the king never escapes the check and the moves are always illegal...?
@@roelandtube The move order could have been Qh4(only move for black), Bg5, Pe3, Ke2 and lastly Pf4 1:04:40
Oh no their queen!
It's really fun and congrats to Simon for solving it in movie time, definitely a hard one if one's chess skills are rusty :) There were a few extra interesting things that were missed:
15:40 move Bg5 (5) has to come after d3 (5) but before the e pawn (2) moves (if it does at all) because it can only go to e3, which means the white lightsquare bishop on f1 never gets the chance to move on the f1-a6 diagonal further than e2 already, and when later g2 pawn (7) is determined to stay still we know the bishop (4) stays in box 8.
1:04:00 some unusual deductions, but not unlike any other variant - the knight on g1 (8) can now only end up on g1 or f3, any cell seeing those two squares cannot be 8, namely r5c7 and r6c7.
1:23:35 16-3=15??
Let's Get Cracking: 06:10
Simon's time: 1h16m39s
Puzzle Solved: 1:22:49
What about this video's Top Tier Simarkisms?!
Bobbins: 3x (27:35, 54:46, 1:15:22)
Knowledge Bomb: 1x (15:35)
Cooking with Gas: 1x (22:25)
Maverick: 1x (07:44)
And how about this video's Simarkisms?!
Hang On: 45x (03:16, 06:24, 07:32, 09:05, 10:53, 11:55, 13:17, 16:44, 21:18, 22:25, 22:28, 25:00, 30:12, 31:29, 31:40, 31:40, 33:10, 33:10, 33:20, 33:57, 35:34, 36:13, 44:09, 46:33, 46:48, 46:52, 46:57, 48:50, 53:12, 53:12, 59:02, 59:28, 1:01:28, 1:01:28, 1:01:28, 1:01:40, 1:03:43, 1:13:46, 1:18:12, 1:19:55, 1:20:28, 1:23:24, 1:23:24, 1:23:24, 1:23:35)
Ah: 25x (09:05, 09:05, 09:05, 21:03, 22:25, 25:00, 25:00, 32:11, 38:50, 39:21, 45:27, 46:30, 46:30, 51:04, 51:04, 53:03, 56:16, 1:08:03, 1:08:07, 1:13:54, 1:15:22, 1:18:56, 1:22:01, 1:23:30, 1:23:59)
Sorry: 11x (11:17, 17:30, 18:08, 20:38, 22:58, 23:40, 53:48, 54:09, 54:30, 1:03:10, 1:10:54)
Pencil Mark/mark: 8x (08:30, 23:44, 59:36, 1:04:11, 1:13:35, 1:16:04, 1:20:08, 1:22:22)
Beautiful: 5x (14:46, 39:43, 39:43, 1:24:41, 1:25:51)
By Sudoku: 5x (1:05:41, 1:12:57, 1:13:04, 1:15:04, 1:15:49)
Good Grief: 4x (14:46, 19:56, 1:22:04, 1:22:04)
Brilliant: 4x (01:30, 02:24, 30:19, 48:52)
Obviously: 4x (01:00, 05:43, 16:40, 27:42)
What on Earth: 3x (59:28, 1:20:33, 1:25:19)
Clever: 3x (25:35, 30:09, 1:22:11)
Progress: 3x (1:09:03, 1:13:42, 1:17:04)
Goodness: 2x (07:15, 15:53)
Break the Puzzle: 2x (10:26, 19:05)
Deadly Pattern: 2x (1:19:51, 1:22:38)
Shouting: 2x (03:52, 04:16)
Wow: 2x (35:14, 1:14:24)
What Does This Mean?: 2x (13:00, 24:02)
Useless: 1x (57:28)
What a Puzzle: 1x (1:22:51)
Bother: 1x (1:16:04)
Apologies: 1x (02:36)
The Answer is: 1x (09:52)
Stuck: 1x (1:06:35)
Ridiculous: 1x (26:39)
Take a Bow: 1x (1:26:25)
Facetious: 1x (09:44)
If I Trust my Pencil Marks: 1x (1:04:11)
Disappointing: 1x (35:49)
Unbelievable: 1x (00:56)
In Fact: 1x (47:42)
Intriguing: 1x (38:26)
Plonk: 1x (1:04:22)
Have a Think: 1x (05:27)
Cake!: 1x (04:22)
Most popular number(>9), digit and colour this video:
Fifteen (3 mentions)
Three (68 mentions)
Red (13 mentions)
Antithesis Battles:
Even (6) - Odd (0)
Black (10) - White (8)
Row (30) - Column (24)
FAQ:
Q1: You missed something!
A1: That could very well be the case! Human speech can be hard to understand for computers like me! Point out the ones that I missed and maybe I'll learn!
Q2: Can you do this for another channel?
A2: I've been thinking about that and wrote some code to make that possible. Let me know which channel you think would be a good fit!
I think there was ("as useful as a") "chocolate tea-pot" in there as well. Not sure if you have that in the filter yet, but it's a recurring Simonism (Simon Says?) that paints a clear picture for me.
Seeing as which puzzle I'm commenting this on...... I'd love for you to make a program like this one for Agadmator's channel!
Rules at 4:30
I do believe that this should be the start of a whole new Sudoku kategory. I could never do this myself but watching it was so incredibly fun! And maybe if more people would do puzzles like this, Sven could Upgrade the App to make it easier :D
I am afraid of Phistomefel getting his hands on this puzzle and adding his Phistomefel rings on a fully chess boarded Sudoku. If Christian and Phistomefel were to work together....
@@HaitiLeonidas don't be afraid. You are not solving them. Only Simon needs to be afraid
I was thinking the same thing. The elements of chess and sudoku meshed so well that this would be enjoyable over and over again
When I first solved this puzzle many months ago I had to use two different grids and a chess board. One grid for Sudoku. One grid to mark which pieces stay put or have to move and the chess board to keep track of the moves. It's absolutely amazing Simon could do this all in one grid.
Totally agree, multi-colors lines changed everything
I did the puzzle without lines, just by colouring the pieces that had moved. Because of that I wasn't able to disambiguate the final 46-pairs as I didn't remember that it was the pawn that was occupying the 6 in box 4 :D
The ordering of the moves was actually quite restricted.
In particular these moves have to occur in this relative order:
...e5
...Qh4
Bg5
e3
Ke2
f4
...Bg4 & Nf3
...f5
...Nf6 & ...Kf7
...Rc8
Which spans 10 out of 13 of black's turns
Yeah, black has a lot of moves that collide with each other when done in the wrong order. Thank you for typing them out :P
This is exactly what i also attempted to do after watching the puzzle..
I was wondering if this is how someone good at chess would attempt to solve it too (instead of looking first at sudoku constraints)
So normally the software simplifies the process of solving puzzles, but this magnificent puzzle is just much more accessible using actual pieces of chess.
I could definitely see that making it easier to understand what's going on. Realizing the black queen would be putting the white king in check, for example, would be much clearer if the queen weren't represented by a 3 that's connected to a queen by a line.
I'm still at under an hour into the watch and so far have made 3 deductions.
1. This is a beautiful but very convoluted puzzle!
2. I was 💯 percent correct in seeing the solve time and deciding to just watch you rather than attempt myself!
3. (Though this one I already knew) you are INCREDIBLE!
Hikaru after looking at the puzzle for 5 seconds: Well this is completely winning for white.
Well duh, because white played Ke2.
Simon, I love the long videos. This , for me, was the greatest of them all. The final force of the Knight move was just amazing. A whole new level of genius. Koenig, you are a master. Well done.
Yes! This is the real chess sudoku puzzle I've really wanted someone to make for so long. Thank you Christian, take several bows!
Super impressed that Simon was able to scan the grid after a few pencil marks. Very confusing.
Yes, as someone who plays chess since the age of 6, i just had mental images in my head where each chess piece stays once i placed it at its final destination.
For example it helped me see the 3 in r7c3 directly without even thinking about it.
3 in r7c3?
40 seconds in and i'm hooked - what a genius of a puzzle 🙂
I would love to see more of these!
Another reason why the knight in r8c7 had to move was that the bishop in r5c7 was giving check to the white king in r7c5 and this could not have been the most recent move, because the black pawn in column 6 moved after the black bishop. So the knight had to block the check.
72:47
Was so confused at the start because the only way I could see the black rook escaping box 2 (because the king was blocked from column 4 by the 3 pawn) was to go forward, but that would push the 5 pawn into box 4 as well which broke the white 5 bishop, which had to go to box 4 because the white 5 pawns took up boxes 5, 7, and 8.
Was a eureka moment when I realized the rook could just go sideways, also proving that all the king side black pieces moved
My favorite logic was when the white bishop blocked the black queen's path to her deduced spot, which meant it had been moved after the queen, proving that the king wasn't in check
So many great moments like this. Loved this puzzle
I love that the final ambiguity about the knight moving isn’t necessary to solve to get the sudoku to mark as solved, but is necessary to fit the rules of chess. A wonderful mini-puzzle that acts as a fitting coda to a magnificent larger one.
To add on the "black has moved 13 times so white have to have moved at least 13 times too", the knight needs to have moved to block the check on the white king by the g4 (r5c7) black bishop, as we know that bishop move is not the last move played, since black still has rook to c8 to play after that bishop move, so the check on the white king must be prevented in some way, and that is the only one that works.
@@Senen33 The sudoku is still solved before working that out though, because both digits are 8s anyway.
@@Jivvi Kinda depends on the order you make your deductions, knowing how many white pieces have moved can help solving some of the black spawn stuff. But yeah you don't need it for the solve.
@@Jivvi Technically, the description says you need to figure out the position as well.
@@danielyuan9862 it's not a solve condition though, and there isn't even a way to enter it into the puzzle. It implies that knowing the exact position is necessary to solve the sudoku, but as he discovered, it actually isn't.
As some already commented, the knight has moved, for the same reason that you deliberated if the black Queen was checking the white King.
Lovely puzzle. Well done Christian for constructing and Simon for solving.
My notation was all highlighting: purple for pieces that didn't move, grey for where pieces used to be, and green for their new locations. I did spend a lot of time looking back and forth to see which greys and greens went together, but I think the reduced visual clutter compared to lines worked well for me.
I used green for pieces which I knew were moving, grey for not moving, and purple once I'd written the digit into the grid corresponding to where they moved to. I found I was able to keep track of who'd moved where from memory (and because only so many moves are legal)
As a chess Master I've got to say that I absolutely loved this puzzle! This is the perfect example of a chess sudoku. I especially liked the final touch of the knight having to move from g1 to f3 in order to block the check (and fit the move count). I can't imagine how someone can come up with something like this, but thanks a lot for taking the time to build it! Brilliant!!
One could determine the position of the King-side bishop earlier! Since the queen side bishop has moved, it means the queen pawn has advanced one step forward. This restricts the king-side bishop to two places, one of which is occupied by the king. Hence, it must have stayed in place.
Do you mean the f1 bishop?
1:06:00 you can deduce that the 8 is C6R6
if 8 is in either positions in C7 in box 6 the knight couldn’t stay where it is because there would be two 8’s in column 7 so it would need to move to the only other position C6R6 which would place a second 8 in box 6 so the 8 in box 6 isn’t in column 7 so it’s in C6R6
Illegal moves didn't come to my mind when solving this, but it's incredible that they managed to be relevant. Christian take a bow! This is truly a one-of-a-kind puzzle!
Sidenote: other than move count, the knight must move to f3 (r6c6) to block the attack from the bishop to the king
Edit: I'm currently getting sidetracked with the question: "Through how many differnet move orders can you achieve this position?" Stick around here for who knows how long to find out the answer.
And the answer is 43,710,624. That didn't take as long as I had expected.
I am commenting just to see if this ever gets an update!
You know, I finished this puzzle but thought the knight moving/not moving was unresolved by the final solution. Thank you for pointing out the blocked checked before I came down here and made a fool out of myself. lol
Like Aurora, I too am commenting in hopes of this one day getting an update.
It has to move to block the check, but if it's the last move then we can't say whether or not it actually *did*. The snapshot that we're seeing could be from just before that happened.
@@7rollface It can't be the last move however: f5 Nf6 Kf7 Rhc8 are four moves that come afterwards
That Christian is simply the best,
For how could one ever detest
A puzzle this clever?
And how could you ever
Beat mixing sudoku and chess?
Watching him bounce between chess rules and sudoku rules were infinitely more entertaining than I could have hoped for! Brilliant puzzle!
IMPECCABLE. Two of the best sudokus of all time in a row. Just astonishing. Love the novelty of this ruleset, so many beautiful deductions, and brilliantly solved Simon, the fact that you’re well-versed enough in chess to get those parts is just awesome!!! PS: the 3 in the corner didn’t get its song! Oh also beautiful guitar playing as usual!
Now I want to see Simon and Mark play chess against each other
Me too
That will literally be a 2 hour game lmao
I'd love to see that. Simon is so good at spatial perception -- but Mark has more of the competitive killer instinct, I think, and would probably pull out some improbable brilliant sacrifice to win the game.
Yes, I would expect this to be more than one video session. Maybe work with the London Park System and do it in public. CtC goes public ...
Incredible puzzle from Christian and solve from Simon! One of my favourite Cracking the Cryptic videos of all time
I was away from home and could not watch this when it was first posted, so I watched it tonight. Guitar intro and outro - lovely. Thank you for that, Simon. And the puzzle and solve - my goodness, I could totally follow what you were doing, but there is no way I could ever do this, even understanding and, probably ,watching the video. You are really amazing when these complex logical phenomena are presented. Thank you so much!
very cute comment, I ageee - Simon, we are thankful for these wonderful videos! :)
This rule set was brilliant! I hope there were app that actually let you move chess pieces to make it more visually clarify.
this has got to be one of the best setting of a suduko ever.....completion and perfect follow through on an idea. Almost a shame there wasn't a chessboard at the end, with the end position displayed
Awesome puzzle!
I loaded final position into a lichess study and found some interesting things.
1. The knight must be on f3!
- If the knight had stayed on g1, Black's bishop on g5 would have the White king in check, but also somehow be nestled in front of the pawn chain -- this position is impossible to achieve with normal play.
2. The position is completely winning for White -- but oddly close to drawn!
Obviously, if play resumes normally from this position, White is completely winning because the black queen hangs on h4. However, if it were Black to play in this same position, the position becomes unclear after bxc4, counterattacking White's queen.
I've recreated the match, it's white's turn.
But frankly, that's not a possible match at all, the moves are absurd
(well the condition was that each piece only moves once so it's not unexpected)
hm... can you link the lichess study in these comments? curious what it would look like.
Thanks for the wonderful rendition of "Is there anybody out there" in the beginning :)
That was 'out of the ball park' one of the best sudoku puzzles I ever solved. The way the sudoku rules interact with the chess rules is amazing. Instant classic!
Don't play chess or sudoku and generally just watch this channel since I find your voice soothing but somehow this puzzle just clicked for me and was able to do it super fast just in my head...
Got me excited since I'm usually totally lost trying to follow your logic even with you thoroughly explaining it every time
I haven't tried the puzzle yet, but I gotta say, Simon looks _amazing_ in the thumbnail.
Hilarious!
This is my first try on any non-classic sudoku. Got pretty far in 20min and was sure I could solve this before simon. But then I spent 80+ min wandering what on earth can I do next? Finally I gave up and came to watch the video.
I don't think I could've figured out that illegal pawn move for king's check in a million years although I play average chess.
The puzzle is absolutely mindblowing. Hats off to Chris.
This puzzle was fantastic, but I have to say it was made way harder by the software not letting me hide the chess pieces and numbers to see my pencil marks. It's hard to read a 5 superimposed on an 8...
Absolutely brilliant puzzle design, though, bravo!
Pure logic pawn!
Jokes aside, I've had this thought on multiple occasions:
A small text box in each cell would be nice in order to comparatively/sequentially number cells or write shorthand descriptions to clarify while solving. Also enable highlighting for this feature and for both corner and centre pencil marks and full colour palettes for the highlighting.
This puzzle is just *chef´s kiss*. The only way I can think to make this...type(?)...more challenging is determining move order.
1:03:29 finish. As a lapsed chess player, I thoroughly enjoyed this. I didn't even consider having to worry about the king being in check, until I got stuck and sat staring at the screen. This puzzle is so unique, I don't even see how it could be duplicated. Amazing!
1:00:05 ... I haven't printed out a completed puzzle in some time, but I just had to with this one. Absolutely mind-blowing; if not the 'greatest' sudoku variant of all time, it has to at least be in the conversation!
Extraordinary!
(I actually counted moves as well to locate the White King's Knight; I overlooked the check-blocking.)
I almost never solve puzzles. But I will spend hours watching this channel.
Beautiful puzzle. I got stuck on the Black Queen check conundrum. Wonderfully done to Christian for setting and Simon to solving.
solved in 40:56 - incredible idea with the chess and all. I was trying to disambiguate between ke2/f2 and ke7/f7 for a long time, then realized qh4 couldn't be black's last move, which rules out kf2. super cool
I don't really know how to play chess but Simon's explaination and hypothecation are so comprehensive that he indicates all the possible moves that special piece therefore letting me understood the rules of chess in the process of Simon solving.
This was lovely, I hope this variant shows up again!
Didn't solve this on my own, but a short while into the video I thought I saw something clever, opened it up myself, and started solving it along with you. I'd NEVER claim that counts as solving, because I was standing on simon's giant shoulders, but it was a GLORIOUS experience, - and even if I was stealing simon's insights, I got a lot of my own insights too. I had the EXACT same moment of horror with the deadly pattern at the end... and had the exact same ECSTATIC EPIPHANY at realising the bishop disambiguated it.
GLORIOUS puzzle, wonderful video. I should have spent the last hour writing, whoops! Thank you again!
Love the guitar intro! Can’t wait to see this remarkable puzzle (I only know a smidge of chess - but find it fascinating)
Memeristor is interviewing phistomefel Tuesday at 11 am, 12 pm your time my friend.
Thought you would like to know, in case you didn't.
Play chess casually with a friend and my dad. This puzzle was phenomenal.
@@davidrattner9 Thanks David! Will we get to SEE Phistomefel??
Is there a link? I’m impressed with people who can play chess - so much to focus on!
@@longwaytotipperary
ruclips.net/channel/UCO3sj30rVauGHsUwt7gmySA
@@longwaytotipperary check above. I linked you to his you tube channel. Let me know if works. Can subscribe to it and set a notification.
Not sure if going to see him or not yet.
I never normally try the puzzles on this long a video. The concept was so intriguing that I had to give it a go though. I had to get a hint from the video about considering checks but solved it in 108:11. I'm now exhausted and may have to go back to bed!
This was so cool! So entertaining and fun to follow. Movie length too which is always a plus!
My solution for this looked like a disco nightmare with all the colour-marks and lines I was drawing. I also needed to peek at the video to work out what to do with the top-right Rook when I got stuck, but after another roadblock with the mess of threes and forgetting that kings can move diagonally, I got it! Impressed with how clean your solution looks.
1:03:00 I found this logic really impressive, recognizing that the "king" must have moved already to make the "pawn" move legal. Spotting an imaginary pin in an imaginary game of chess in a Sudoku is just fabulous!
This puzzle is a masterpiece. Chess and Sudoku have never been merged so smoothly. And congrats Simon, as usual!
These moves recreate the final position, though it makes for quite a bizarre game!
1. b4 e5
2. c4 Qh4
3. d3 a5
4. Bg5 b5
5. e3 d5
6. Ke2 Nc6
7. f4 Bg4+
8. Nf3 f5
9. h3 Bd6
10. Rh2 Nf6
11. Qb3 Kf7
12. Nd2 Rhc8
13. Rd1 Rab8
Good catch! Here's another one:
1. d3 d5
2. h3 e5
3. Rh2 Qh4
4. Bg5 Bd6
5. e3 Nc6
6. Ke2 Rb8
7. f4 Bg4+
8. Nf3 f5
9. Nd2 Nf6
10. b4 Kf7
11. c4 Rhc8
12. Qb3 a5
13. Rd1 b5
The crazy thing is during recreation the engine spasms out but the actual position is almost no advantage for either side.
@@danielsharp2402 The final position is +12 according to SF15.
Loved watching the solve. I couldn't help but think that highlighting the pieces that need to move in green and and the pieces that stay still in red might have helped a lot to see which pieces you hadn't looked at yet and whether they needed to move or not. You could even highlight the square they move to in a different/same colour to help with the visualisation. Thanks for the lovely long video!
I'm so impressed that a puzzle like this was able to be created. Crazy amounts of logic and love must have gone into setting this
Genial Christian, ein unglaublich schön konstruiertes Puzzle!! Und Simon, wieder einmal ein beeindruckender Lösungsweg. Ich brauchte 3 Stunden für dieses Meisterwerk!
This was an amazing ride. When it dawned on me, that not just moves, but also the resolving position determined the placement of pieces, I finished quickly, but with my jaw dropped, in total amazement.
Now I am waiting for a Go-Minesweeper-Sudoku hybrid…
When trying to figure out where the Queen goes around 34 minutes in, I was screaming at my screen because Simon failed to realize you can't put the queen through the rook, locking the 3 of the Queen to the 2nd column. I'm not sure how much of an impact it has on the puzzle but it hurts to watch. Bobbins!
Great puzzle. The logic about the queen checking the king in particular was beautiful.
Lovely puzzle. It was actually way easier and approachable than it first seems. Would love to see another of this ruleset.
I am a decent chess player and have some experience in solving proof games. So, a few points:
1. This is a brilliant puzzle
2. See 1.
3. How the f do you set this
4. Probably the puzzle is not suitable for most of the channels audience.
5. Probably the puzzle is not suitable for being solved in CTC Software
6. See 1.
I am amazed, congrats to Christian for an absolute masterpiece! The disambiguation whether the g1 Knight moved or not is the climax...
And yes, some chess knowledge does definitely help. A lot of deductions, involving pieces switching place for example, came (more) naturally to me.
Another possibly interesting puzzle would be finding a legal series of moves to end up in the final position. There's enough dependencies it doesn't seem trivial (e.g. the white dark squared bishop must've moved before the e and f pawns, but after the d pawn).
Here they are: 1. b4 e5 2. c4 Qh4 3. d3 a5 4. Bg5 b5 5. e3 d5 6. Ke2 Nc6 7. f4 Bg4+
8. Nf3 f5 9. h3 Bd6 10. Rh2 Nf6 11. Qb3 Kf7 12. Nd2 Rhc8 13. Rd1 Rab8
Indeed. Maybe the given numbers help with that. King pawn moving first, then the Queen pawn on white side.
I *almost* managed to this one by myself, but the idea of preventing checks just didn't occur to me. Brilliant puzzle!
I was in the exact same situation. I found two different, seemingly viable solutions, but as soon as I realised I had to bear 'check' in mind, it resolved my fork.
@@g00w haha "fork"
I can't believe I finished this puzzle! Very beautiful! It took me a little under 23 minutes. I love it!
A useful way to pencil mark in order to be able to "read" the board was a colour for each type of piece, used for the square it landed, or was confirmed to have stayed (together with line tool in same colour). I used Blue for Bishop, greeN for kNight, Red for Rook etc. Also marked confirmed empty squares in pale grey making it much clearer which pieces needed further consideration. Now if only I'd spotted all the other stuff as fast as Simon....
I finally tried one as I felt this was the first time I got off to a quicker start than Simon.. I got really far but then I had to go back to the video to cheat a bit and I noticed.. I forgot the king was in check at some point. After that my puzzle fell like a house of cards so it was the final piece I needed.
Still, this was a very entertaining puzzle!
To answer the question from 38:32, as a chess player, I definitely think that helped me to think through this puzzle. In watching your solve, I consistently came up with concepts like restricted digits a lot faster than you did, which I think is down to my chess experience.
That said... I did try the puzzle on my own before watching and didn't get very far, as the sudoku part of my brain is not nearly as well honed as the chess part. I'm pretty sure I could have gotten there eventually, but I reached a point, after about 45 minutes with only some 5's in the grid and some knowledge that 3 was restricted, when I decided I'd rather watch a pro do it.
I think that sudoku experience is more important to solving this puzzle than chess experience, but I think that chess experience definitely helps. In other words, an experienced chess player with a casual knowledge of sudoku (me) would have taken hours to solve this, an experienced sudoku solver with a casual knowledge of chess (Simon) would have a much easier time, and an individual with experience in both would have an even easier time. This was a really fantastic puzzle, and even though I couldn't solve it myself I really enjoyed it.
Simon, there is ANOTHER way to know whether the knight on g1 moved. Can you see it?
Black played Bg4! If white did not play Nf3 beforehand, Ke2 would have been illegal.
(this is way cooler than counting moves IMO)
And you have to remember that Black has played f5 also, which had to come after Bg4. Otherwise the final move could be Bg4 with check.
Agreed partially. White cannot play Nf3 before Ke2. Can you see why?
@@wolffang21burgers Oh, right! Ke2 was before the f4 push! My bad, did not catch that.
Heh ... I did it by counting moves. Nice alternate!
Love how at 14:14 he used completely new logic on why the bishop can't be in r6 instead of continuing his swordfish logic
While playing with the puzzle, I discovered a second solution only if you allow the king to be in check. That one rule creates a single solution puzzle. Oddly if you had ignored that point and put the king in check, you would also have found a second solution for the sudoku part of the puzzle.
Tried to do it on my own but I just couldn't get past the the first few fives and ones, so I followed along and with every hint of yours stopped the video and tried it on my own again. I actually got the hang of it after some time yet it still took me 92 min to finish. This was tough, wow! Also to Chris, just wow!
This is actually the first puzzle on the channel I’ve ever solved faster than Simon. A fantastic feeling
I think this is the first puzzle I solved faster than Simon (it took me just under 54 minutes). As a relatively advanced chess player (1900 USCF), I think I had a slight advantage with solving this puzzle, but not necessarily a large advantage. The main things were very quickly recognizing all possible moves for each piece as well as possible checks.
At the end, Nf3 is required, else the white King is in check from the bishop on g4.
Wowzer what a puzzle. Absolutely loved the fact that you needed to play out a part of the game to resolve the white King. I'd consider that the "breakin"... and a delayed breakin that's 3/4 through a puzzle ?!?!? I've never seen that before.
I would have used a color for each piece type, probably easier than whatever simon ended up doing, looked hard to parse to me. May give myself time to forget the solve and give it a go, but was intimidated by Simon's solve time.
Great puzzle. I was stuck for so long, then decided to watch the video. When you talked about how the white couldn't put itself in chess when pushing the pawn, my mind was blown and suddenly all the last pieces fell into place.
From an abstract view, the mechanic of being given a digit that fits along a line is very interesting. Made for a lot of interesting thought paths.
So many markings used to keep track of things since it was so hard to read the numbers overlapping any pieces made for possibly my busiest grid in the end.
An excellent puzzle indeed. I love that you figured out the knight at the end a different way than I did. My logic was that white would be in check at the end if the knight didn't move which would be fine except that black has to move a rook after moving that bishop.
this is so cool, we need more chess puzzles like this!!
Finally, after 3 days, and 3 restarts of this puzzle, I can finally watch this video. As a someone who loves chess I've never been so determined to solve one of these puzzles for myself first. This was a fantastic puzzle.
Nice puzzle, but it's incredibly confusing. Here's a couple of generalised suggestions for the interface which might have made the puzzle easier to solve:
a) The ability to default corner pencil marks to the top right corner of a cell
b) The ability to delete elements from the puzzle setup after the solve has begin
I made surprisingly good progress here, but after minute 67 I noticed that I couldn't put a 5 in box 8 anymore (all not filled cells had a 5 looking at them). Must have been some mistake somewhere.
I restarted, and the second time it took me 109:27. (At the end I was stuck for a while, until I looked at who is attacking what, which resolved the positions of the white king, and from there the rest followed.)
For notation: I picked different colors for the individual pieces (dark gray for pawns, red for rooks, orange for knights, yellow for bishops, purple for queen, green for kings - I omitted blue on the second try because that made the pencil marks and final digits harder to read). Then I used the pen tool to mark the origin spaces with circles (if the piece could still be there) or crosses (if I knew it had to move away) of the same color, and used the cell fill color tool to indicate the location where a piece moved to (or stayed) (with partial coloring if there were multiple options).
Due to the "one move only" rule that was mostly unique (just the rooks could possibly see each other, but that still was not a problem).
In some cases I also used the lines of the pen tool to mark the moves of the bishops and queens (but removed that as soon as I got a position, as it would be too cluttered).
I'll watch Simon solve this tomorrow.
Just saw the check logic. absolutely brilliant. this is now my favorite sudoku of all time.
at about 1:05:00 you could've deduced that the bishop could not move because of the order in which the other pieces moved. there wasn't a moment where the bishop was free to move, since the king only moved out of the way after the pawn on d2 blocked its diagonal to free the other bishop, which moved before the king
Best “chess sudoku” ever. 32:45 ✔️solved quickly using a chess board and labeled pieces/sticky tabs 😀
That - Was - Awesome! The puzzle as well as the solving!
Wow, what a puzzle! Took me 150 minutes. I used traffic light color coding: pieces that move are green, pieces that don’t move are red. This helped me realize “I’m going to need to move at least two more white pieces” after finding that sweeping black rook move. It also resolved the final “did this knight move or not?” question. Yes it did, because otherwise black moved more pieces than white did, and that’s not allowed
I also did reverse thermo markings: lines to show a piece that moves, just like you, but a circle where it ends to distinguish where one piece follows another.
I had a great time solving this puzzle (56min 3sec), but after recreating the position with chess pieces, I've come to the conclusion that neither player knows how to play chess very well. Black's queen and bishop are both being attacked, and based on the position, must have been for several moves. Not sure why both players decided to go with somewhat of a "bongcloud" opening (If you're not familiar with chess, look it up). White has a terrible bishop on f1, and I'm not sure why you would ever move the rook to h2 (but funnily enough is actually pretty well placed as taking the bishop on g4 will come with a discovered attack on the queen, while defended by the knight, assuming black has the next move and will finally notice their queen under attack). Neither player seems to have a concept of where to place their rooks, based on which files will open up (besides rook on h2).
Stockfish (chess engine) determines that white has a +13.6 advantage, which is pretty crazy considering not a single piece has come off the board yet. Shows how absolutely terribly black has played, even though white is not much more skilled.
If anyone is curious, the browser stockfish on Lichess has white up +11 in this position (mostly because the bishop on g5 or sudoku r4c7 takes the black queen basically for free)
That black queen has been hanging for forever... It's black's turn to move in this position though.
@@beakerfozzie6881 I think they have made an equal number of moves, so it should be white's turn to move. I could have miscounted, though
1:06:02 That 8 had to move to R6C6 because
If the Knight Moved its the only space it could move to
If the Knight didn't move the original square would be 8 which would eliminate the other 2 C6 by sudoku
50:40 Because white's D and E pawns are both restricted to the 2nd and 3rd rank, it is not possible for both bishops to move though that 2x2 box, as the C bishop needs the pawns to be at D2 and E3 while the F bishop needs the pawn to be at D3 and E2. These two combinations cannot exist within the same game. From that the F Bishops cannot move through the box as the C Bishop has already done it.
Truly a brilliant puzzle! This was the first CTC feature where I watched the first few moments, then IMMEDIATELY went to solve the puzzle myself, and then returned to watch the rest of the video! :)