Thanks to a couple of comments I've noticed that there is a flaw in my logic at around 50minutes into the video. I worked out the line in box 1 had to have a 9 on it and then thought this meant it had to have a 4 on it too. (I did the same thing at a different moment in the video but caught myself that time.) It's actually not easy to show this line must also have a 4 on it but here is one way you can do it: 1. Note that 9 must now be on the line in box 3 in r2 by sudoku. 2. Note that 1 cannot now be on this line in r2 as well. [This is a quite beautiful point. If you try and put 1 on the line with the 9 in r2 then it is either next to the 9 making a 10 domino or it will make the alternation along the line incorrect!!!] 3. This forces 1 in box 3 into r1. 4. Now look at r2c7. This digit can only be 4/6/9 as any form of yellow 2378 will create a 5/10 domino with r2c6! 5. But this digit also cannot be 9 because (and this is ANOTHER brilliancy from Phistomefel) the other two low digits on that Whispers line in box 3 would now be a 2/3 pair summing to 5! 6. It also cannot be a 6 because this would need a 1 next to it in r2c8 and we know the 1 is in r1 in box 3. So this digit is actually a 4. This forces a 4 onto the Whispers line in box 1 and the logic I did find can continue thereafter. Apologies everybody. Let me know if it might help if I made a short video to explain this.
On 5.: I still have r3c8 as being possibly 4, which wouldn't cause the 2/3 pair summing to 5 problem. That would require a 9 next to it in r2c9 though, conflicting with the 9 we're supposing in r2c7, so it still effectively rules out the 9. I think this catches it! Thank you!
The restrictions on 4 in box 4 eluded you for great time after placing the six. then at 54:04 you placed the pencilmark 4's in box 1, straight up shouted X-WING! at the computer. Cannot and will not ever be able to do what you do, and even keeping up with your logic or spotting something 10 mins before makes me feel so smart :') But the best thing is just to see you get so happy and genuinely touched by the logic and effort people put in their puzzels. You're a joy to watch
I’ll alledge there’s more. Level 1: Easy, Level 2: GAP, Level 3: Medium, Level 4: Hard, Level 5: Really difficult, Level 6: Monstrous, Level 7: Ridiculous, Level 8: Absolutely Ridiculous, Level 9: A level I call “what on earth is going on here”, Level 10: Impossible, and then… Level too insane to be confined by something as simple as a number: Phistomefel, the ultimate boss
C'mon it wasn't that difficult, I only did it in 3 hours, with intermittent breaks of course for my brain to rest so that it recover from overheating thinking about the whisper lines and negative constrains and my color scheme where yellow pairs with blue but not green which pairs with orange which can pair with blue but not yellow. So yeah not that difficult at all.
Agreed! Sometimes I tire of their use of SEO by titling their videos relevant to current popular search trends, and I'm always happy to see the authors of these wonderful puzzles featured more prominently (Even in this case when we know Simon already obviously fawns over this author incessantly)
I'm pausing my watching of the video (at around 37:30) when Simon says that he has tears in his eyes. THIS is why I love this channel - not only because of the quality of the puzzles, but mainly because of the enthusiasm and genuine pleasure that Simon and Mark have in the beauty of the logic and the thought that goes into these hand-crafted puzzles. OK, now resuming my watch ... I am sure I will be equally impressed in the coming minutes of this video, but I had to pause now so that I could capture this thought.
rules should have been: 2 adjacent cells summing to 5 or 10 are marked with a V and X respectively, all X and V are given. This would have sounded a bit more intimidating
@51:20, proving there's a 9 on the line doesn't immediately prove there's a 4 on the line. Takes a few extra steps to eliminate the 4: The 9 on the line in box 1 forces a 9 onto the line in box 3, and that prevents a 1 being on the line in box 3, forces the 1 into r1 of box 3, can remove the 1 pencil-marks from r1 of box 1. Now 4 can't be in r2c2 as it would be next to a 1. If 4 is in r2c3, there's nowhere left for 6 in r2. If 4 is in r2c1, that forces 1 & 6 in r2, leaves only a single low digit remaining in r2, the yellow 23, which must go r2c8 for the box 3 line to work. That must be surrounded by 9 and yellow 78, yellow 78 can't go next to the green 23, so r2c7 is a 9, r2c9 is the yellow 78. And now r3c8 has no fill. Can't be 1 as it's already in the row. Can't be yellow 23 as it's already in the box. Can't be green 23 as it's next to yellow 23 and would sum to 5. Can't be 4 as it's next to 78 on the line. So it's broken, and that proves the 4 you assumed on the line in box 1 is really there.
the last bit of logic that clears up the 7/8s & 2/3s is so beautiful. The "odd one out" hook-shaped whispers line coming back to be relevant just feels so satisfying (especially since my first thought at seeing the puzzle was: "that is different from everything else, it'll be important for disambiguating something important." my first instinct was to start there)
What an absolutely ridiculously good puzzle from Phistomefel and a solve of near-equal proportion, especially when combined with the very well written pinned comment. Just absolutely incredible. I have no idea how this channel isn’t huge. This channel deserves AT LEAST 1,000,000 subscribers, but I would’ve expected it to have double that by now. Stunning logic, cool ruleset (Anti-Roman? Perhaps call it Greek?), and yet another beautiful combination of one of the best setters in the world and one of the best solvers in the world. Bravo.
There's a neat way of thinking about the horseshoes at the start: Horseshoes never contain a 5 or two digits adding to 10, so they must have one 1 or 9, one 2 or 8, one 3 or 7 and one 4 or 6. This avoids having to enumerate all the cases by hand.
Absolutely the most sublime final disambiguator of a puzzle I have ever seen. Staring at an almost completed grid with nothing undone left but 23's and 78's in every box and going "I know this must resolve, but how?" and then the resolution was just amazing. And it's not through an added element, like a given digit or an inequality sign, or a stubby thermo -- just brilliant. Honestly from the very beginning I thought "Hmm, whispers puzzles usually have to have something to disambiguate hi from low, but there's nothing here but the lines. How odd." When I placed the 78 on the whisper line in box three I thought it might be significant that I couldn't determine which flavor of 78 it was (my Spidey sense was tingling as Simon would say), but it was even more beautiful than expected. What a finish. Just over 2 hours for me. I didn't make the unjustified leap Simon did to place 4 on the line in box one with the 9, but even my best attempt at self delusion cannot convince me that made up for the 40 minute difference in solve times! In a just world this would have at least 10 million views.
"Self praise is no praise". Okay then Simon: I'm proud of you! I didn't even bother trying to do this one even after watching the break in. A masterpiece.
Shouting tends to be two different ones - You Are All Shouting At Me (for missing logic or the obvious) Shouting(going on) for when the kids are on holiday and playing downstairs or in the garden
In my mind, I'm imagining a scenario where Phistomefel isn't actually a mad genius. Instead, he's just incredibly lucky. Each time he wants to make a new puzzle he draws a couple of lines, randomly assigns a ruleset, job's a good'un. In this reality he's baffled by his success, and is constantly worried that one day he'll draw something wrong and the puzzle will consist of only deadly patterns.
A sublime work of genius. Phistomefel doesn't just create magnificent puzzles but new discoveries around patterns (which we, ably guided by Simon, are allowed to discover). How such visual simplicity leads to such an extraordinary line of logic leaves me gobsmacked.
At 1:04:38, you could resolve box 9 as the 2,3,4 are all ruled out of the whisper line. Since there has to be a low digit, you can place the 1 on the line and forcing the 9 into rows 7 and 8 by the XV restraint. This would get you those numbers in box 7 as you had suggested might be possible
"Don't get any ideas constructors out there!" Someone probably just thought "Challenge accepted, I'll make one of the digits on each German Whispers Line a secret 0 or 10, which a 5 can be next to."
Nice. I was thinking more along the lines of digits must be between (minus)9 and +9. With the row, column, and box totals being +/- 35... [Edit: RUclips seems to hate negative numbers in comments. How self-protective. 😉 ]
@@DanielHShead Every cell contains the digits 1-10 (plus or minus). The sign may be different vertically and horizontally. What kind of hell have we unleashed on sudoku? I'm sorry, Simon and all. But I think this will happen. I still need to trace through the whole "wrogn" thing where I'm fairly sure a flippant remark like this led to it being actually made into a real puzzle. OP is right. The puzzle setters need a challenge too. And a word to the wise; they are vastly more intelligent than we are...
As always the sudoku setter master is able to use a simple ruleset and produce an extraordinary and unique sudoku. I managed to solve this in exactly 1 hour and I am happy with that!
In some weird way, Simon makes me feel smart. I find a number or even just understand the logic during the solve and feel proud. Don't know how you do it Simon. :)
Just under 2 hours, although I did have some distractions along the way. This was an absolutely BRILLIANT puzzle. As Simon would say, it's "classic Phistomefel" in every way. Absolutely loved it.
Wow! Very satisfying to solve it unassisted. Hit a brick wall after three hours but after a good night's sleep woke with fresh inspiration and finished after another hour. Hats off to Simon or anyone who can do this in less than two hours. Crazy puzzle.
I was able to solve it, I think it's the first time I could tackle such a big beast! It took me some more than two hours. Yet one thing that helped me a lot, at my own pace, but I believe would have been helped Simon to do it faster was to pick a color for each domino tile value (so, all but the 5). I picked "friendly" colors for the dominoes members, hence yellow/green and blue/magenta were the high/low for the 78/23 dominoes, red/orange and black/gray for the 61/94 dominoes. By combining colors it became way easier to scan the grid and find matches and mismatches. Another thing I am doing when pencilmarking, is to use the 0 as a placeholder for "and something else", so it help me make partial pencil marks while keeping track that there are still missing digits to ponder. So, by writing in the cell center "092" I know the 92 are candidates, yet not the only ones even when I still didn't figure out the others (I guess it'd be great to have an unrestricted pencilmarking, allowing characters and other symbols, much like regular expressions to express sets of alternatives or to exclude values).
This puzzle is brilliant. I love minimalist constraints like this. The emerging logic with 2-7 and 3-8 pairs propogating through the grid was quite satisfying to discover. Took me over two hours, and I only got unstuck around the 40 minute mark.
I had to( in a way) biforcate around how the horse shoes worked I suspect there is a way to figure it out simpler then the path that I took. Loved the puzzle took me two days with a break. But so fun can't wait to watch the video.
What an amazing puzzle !! When Simon has to solve a mini sudoku before even beginning to solve the entire sudoku, it says something profound about the puzzle itself. Loved the solved as always !!
50:35 Did I miss an explanation on why having a 9 on the whisper line requires a 4? A 4 requires a 9 but I'm not immediately spotting why (23)-9-(23) or 9-(23)-(78) doesn't work.
Yeah, Simon has done it again. The way to prove this is to first notate the 9 on the Whispers line in box 1 (that we've just proved) and then notate it on the Whispers line in box 3 (top three cells of the line). Now regardless of where you place the 9 on the Whispers line, a 1 couldn't accompany it since it can't sit next to it (10-sum) nor have a square in between them since it breaks the high-low principle of the Whispers line. Therefore, in row 2, 1 can only be placed in box 1. At this point if we assume 4 wasn't on the Whispers line in box 1 we'd have to place it in one of the three cells above it in the same box. This gives us a 1-4 pair in box 1, leaving the central cell empty because of the 5-sum rule, and as a result, a 6 lives in the top part of box 1. Now, in row 2, we have relatively placed 3/4 low digits, so on the top part of the Whispers line in box 3 we can have at most one low digit and to abide the high-low principle it must be in the center, ie the central cell in box 3. As there's a 1-4 pair in the row this cell is either 2 or 3. Again on the same Whispers line, by the high-low principle, the cell directly below the central cell must be a low digit. Better yet it must be a 4 in order not to create an orthogonal 2-3 pair which breaks the 5-sum rule. All the pieces are there and the punchline is you can't place a 6 in box 3.# There's a 4 on the Whispers line in box 1.
this is one of the best and beautiful solve paths I've seen (working through this in vaguely chronological order, a year behind 😂). superb that it gets coloured completely then that last whisper resolves it. phistomefel is a complete genius
It took me nearly two hours (I clocked in at 1:43:39, but it was probably a few minutes beyond this), but I was able to tame this behemoth. Stunning ... simply stunning!
The way that you figured out that there was a forcing sequence with the horseshoes was nothing shy of brilliant. Just noticing that the horseshoes only had four potential configurations was more than I ever would've gotten when attempting this puzzle.
I watched and marveled. I got that it had to do with constraints in the horseshoes but gave up before working through them. I appreciated Simon writing down options. I will do that next time and maybe advance a bit further.
currently in the middle of replaying all of the sudoku apps:)) one of my favorite pastimes now a days is listening to creepypasta readings while solving sudoku puzzles via cracking the cryptic apps. hope u guys are planning on more updates/puzzles/apps for the future because im really enjoying them:D
Phistomefel should have called this XV Whispers with the XV constraint listed in the rule set along with “All instances of orthogonal digits summing to 5 or 10 are given.” And then Simon would be even more incredulous with NO XVs and just negative constraints! Very powerful and yes, this was just a popcorn episode for me.
I really think this is one of the all time great puzzles. The combination of simple rules, sparse grid, and challenging logic start to finish. Extremely elegant and unique. First time through I solved thanks to (a) an egregiously lucky error and (b) trifurcation (lol) on r2c7. On watching the video, Simon's early steps were much cleaner than mine (as usual). I do have a quibble at 50:04, I don't see how he's proven there's a 4 on the box 1 whisper line, but the 9 is certainly proven and that fixed my solve. Reworking from that point it puts a 9 on the whisper line at r2c7..9, and you can easily resolve which cell it's in. Many thanks to Phistomefel and Simon.
@@MinecraftTheCreators Hmm I think I made my comment on an un-refreshed copy of the video, I didn't see the pinned comment at the time, sorry for the duplication.
69 minutes exactly here. I found that really tough but then that's to be expected given the identity of the setter. I enjoyed it though. Amazing puzzle at first glance, my initial reaction was "How on earth am I meant to start this?"
This video deserves a cinema trailer. Like this: *Dramatic drums* Bass voice:THIS WINTER ... Simon:Oh dear ... Bass voice:From the creator of the most creative puzzle ... Simon:God grief ... Bass voice:Phistomefel ... Simon: absolutely genius ... Bass voice: with the famous puzzle cracker Simon Anthony ... Simon: we've broke the puzzle ... Bass voice: GET READY TO BE CRACKED ... Simon: let's get cracking ... Bass voice: now on RUclips! :D
50:35 Got scared here. Your proof said that the 9 has be in the line, but the 4 could still not be in it. It could be 3-9-2 still. Or 8-3-9 and others. Luckyily it turned out right in the end!
A video of Simon just reading off names? … I would watch that video tbh. I’m fairly new to this whole channel and deeper sudoku puzzles. I absolutely LOVE you guys! Thanks for opening this new world to me ❤️
When you mentioned this puzzle a few days ago I set myself the challenge of solving it before you posted a video of it. I definitely needed the head start, but got through it. Brilliant puzzle as always.
Wow! What a Phistomefel puzzle! The interaction of the 4-cell German Whisper rings and the anti-XV rule set is just stunning, although it took me an hour to figure it out! But even afterthat, there are still more and more logics in it and every time I spot the beauty of them, I just feel "Wow, how can sombody come up with this?!" Finally I used around 2 hours to solve it. I haven't watched the video yet but I am looking forward to the solving of Simon. (I am from Hong Kong, so please forgive my bad English.)
Agree. Also, I think there does need to be an agreed way of writing rules. Standard sudoku rules apply, standard Thermo rules apply, standard VX rules apply - all XV's given etc etc
I didn't even had a start when I tried this puzzle so I religiously followed your logic on this one... But I had an interesting thought at 1:05:22 which is the following: At this point I was wondering "how can you tell appart which color is the 3-8 pair and which color is the 2-7 pair". And o figured out that the only way was to use German whisper's line rules, and to have a green and yellow cell next to each other on a line (this was because no 2,3,7 or 8 were placed and the only rule playing on numerical value was the whispers line). And as they can't be orthogonally connected, they needed to be neighbors on the line in box 3. So if r3c8 wasn't green, the puzzle wouldn't have a unique solution, which isn't the case. Therefore, r3c8 was green 7/8 and, since it is next to a yellow 2/3, it was an 8. I really like the logics involving the unicity of the solution in a sudoku, so I was proud of that one.
This sudoku is simply stunning! It turns out that the start doesn’t even require you to guess the parity of the whisper lines, you can just use colours and logic to isolate the options as follows; There are exactly 2 ways of making the ‘horseshoe-shaped’ German whisper lines work if you ignore the combinations of 2,3 and 7,8 pairs (4 - 9 - 23 - 78 and 6 - 1 - 78 - 23). Since we know by sudoku that the whisper lines in boxes 4 and 5 are different (the 4,6 pair see each other in row 5), the 2nd and 3rd cells respectively on each line must be of opposite parity and appear in the middle of the line (though we don’t yet know the order). This is particularly powerful for the 1s and 9s, since the 1 or 9 in box 4 is forced into column 6 of box 5, meaning the whisper line in box 2 must be the same type as the whisper line in box 5 (both must contain a 4 and 9 or a 6 and 1). By similar logic, the 1st and 4th cells on the whisper lines cannot be in the centre of the horseshoe, so the 4,6 on the line in box 5 must go in the bottom leftmost cell (it will see the same digit in box 2 otherwise) and this determines the order of both lines (remember that the 4,6 pair in row 5 must be kept apart in order to not create a domino adding to 10). Now we can colour the 2,3 and 7,8 options. The cells on the whisper line in box 5 must be of different parity and cannot add to make 10, so we can colour them red and yellow respectively (we are treating red and blue as one of the pairs adding to 10 and yellow and dark grey as the other). The important step is to realise that the 3rd cells on the whisper lines in boxes 2 and 5 must share the same parity. So we may not know exactly where the 3rd cell on the line in box 2 is but we do know its colour (blue and yellow are both opposite parity to red, so it must be dark grey) and that it appears in column 3. This places dark grey in row 6 column 4, since it cannot go next to yellow (they would add to 10) and the fact it is of opposite parity to the 3rd cell on the whisper line in box 4 makes that cell blue. Now blue only has one place to go in box 5, as it cannot go next to red (again, it would form a pair adding to 10) so must be next to yellow. But we know that yellow and blue are the same parity (as red and dark grey are the other parity) so they cannot be from 2 and 3 (or else the domino would add to 5) and thus must be from 7 and 8, which fixes the parity of the whisper lines in boxes 2, 4 and 5. Hopefully I didn’t mess up anything in that explanation. A genuine thanks to Phistomefel for an incredible idea that made for an amazing solve. :)
52:54 "You've all been shouting at me for about a minute and a half haven't you?" Ok, first of all I don't know how I got so into a video about solving a sudoku that I was shouting at the screen and second of all I don't appreciate being called out, Simon.
This really looks like a miracle. New ruleset and stunning logic from start to finish 👏. I used different colouring for 23 and 78. I believe it makes everything more familiar and hence easier to grasp (at least for me): green 23 ➡ green 23 green 78 ➡ blue 78 yellow 23 ➡ yellow 23 yellow 78 ➡ purple 78
And once you see the logic, it isn't even mad genius logic. It's simple beautiful logic. Every time it happens you say oh yes of course, instead of... WTF
What an amazing puzzle. A clean way to get initial digits is to introduce 4 colors for pairs that sum up to 10. You can then prove that U-shaped lines consist of 4 different colors - since each element must be different than its two neighbors (to avoid 10 sum) and different than last one, since whispers would make it same digit. I really struggled with putting digits on the top right line - both with putting 9 there, but also later with 4. Funnly enough - once you have 49 there, you actually can prove 78 is yellow (54:54, after conclusion from 56:30). You need to consider color of 23 on the top left line - if it is green, you will need to put yellow 23 and green 78 in the top row of that region; with neither being in the middle (10 sum) they will collide with 6. That 23 being yellow forces green 23 as a neighbor of 78 in question. (Would be nice if I noticed that before incorrect conclusion that it is green and reaching a paradox)
Yet another brilliant epic. I had to have a separate screen with the horseshoe possibilities as couldn't keep it all in my head, glad to see Simon doing the same.
I solved Balance Loop the other day without too much trouble, but I looked at this puzzle, worked out a little bit about the horseshoes, but just couldn't get the break-in. Thank you for the solve. I repeat your self praise to you that it may gain value, and I ridicule you for trying to put a 4 in the middle of a German Whispers line.
Sorry, I do want to do the usually comment section of some bad logic: You mentioned at the end of the video that "Self praise is no praise at all." Out of all that, you can't get yourself some self praise?!? Nope, not logical. Please unwind and give yourself the praises! But really, be proud. This was an amazing solve of an amazing puzzle, by an amazing constructor. ALL THE SELF PRAISE!! That's all. Thanks for the movie before bedtime :-)
Simon: brilliant logic, explaining at the start how 4 and 6 can only be at the end of the line. Simon, 40 minutes later: wondering where would the 4 and 9 go on the line. If this isn't me 90 % of the time, idk what is. The loss of focus is too real. EDIT: the 'why is my brain not working' part is also very relatable, don't worry Simon, you're a genius anyways, losing focus for a moment isn't your fault!
I did the last step a bit earlier and different: since r2c6 and r2c9 are green and yellow 23s respectively, and both connect to green 78s on a whisper line, green 78 has to be 8 to match whichever of those is 3. So I had my 2378s sorted out long before finishing the rest of the puzzle. Incredible puzzle and solve as always.
I'm days late, and self-praise is indeed no praise, but I was particularly happy at being able to solve this one, however slowly. I just loved the series of epiphanies as the logic unfolded from the 46-19 interactions to coloring the 2378 dominoes.
I managed to do all the hard logic somehow, but failed to see 1 in r3c5 forcing 4 to be at the top... Well, I'm fascinating of brilliance of the installation. I wonder how's the author come up with such an idea! Simon, great job, congratulations!) And thank you for bringing this to me :)
What a delight of a puzzle, thanks Phistomefel! And Simon, my rusty brain does a calisthenics class watching you solve 😄, whilst having fun! Thank you!
1:24:57 "... and I'd love to know how many of you finished it" - bro, whenever I see a phistomephel puzzle I know that I'm not even going to attempt solving it. I just get the priest into my room to exorcise it and then I get the popcorn and watch the movie
4h20m. Similar path to Simon's but I used four colors for 23/78 instead of two colors and I think that made it harder for me to spot how box 3 was different from box 5 at the end. Very hard but very satisfying puzzle.
This was a lot of fun, as always with Phistomefel. Using distinct colours for the 2/3/7/8 worked well for me, as I find "yellow 23" a bit cumbersome - this also made filling in the final digits easier. I made a stupid error towards the end but then when I did the final fill-in, one of my whisper lines was broken. Easy enough to rewind and spot the error.
At 51 minutes, what's the justification for the line in box 1 having *both* 4 and 9? I think all you proved was that it needed 4 *or* 9 (which easily leads to needing a 9, but 2,9,3 for example looks fine at that point).
Okay, have finished the puzzle and now its time to watch Simon get lost in the devil's labyrinth. German whispers are now my favourite variant; Oh and I shall derive immense joy if Simon chooses the similar colour scheme to resolve the whispers. (Edit: Brain - Immense joy received)
I solved my first Phistomefel puzzle a few days ago (and no it wasn't the 1 star one haha) and i'm very proud of myself, i saw this puzzle on LMD and i was amazed by the minimalism in the grid, can't wait to watch.
The rules should have explained X, V and ended with all Xs and Vs are given. I think that would give you a moment of "that's useful" which immediately turns into "oh no" once you look at the grid. :D
I think this would only work if you had seen an XV puzzle before. If this was the first XV puzzle I'd ever seen, I'd just be convinced the grid wasn't loading correctly in my browser and move on.
This is just a beautiful puzzle. No idea how such a thing gets set. Wondering whether Phistomefel has been studying Simon's solving techniques (and/or psychology). Simon, I find your solving compelling - sometimes I see things ahead of you, but the consistency with which you find helpful techniques (eg the colouring in this one was non-standard) is beyond my capability. I learn something new every time.
Still watching it, but why must the whisper line in box 1 contain a 4? I see it must contain a 9 but not necessarily a 9 AND a 4 (at least without going into any further logic)
Thanks to a couple of comments I've noticed that there is a flaw in my logic at around 50minutes into the video. I worked out the line in box 1 had to have a 9 on it and then thought this meant it had to have a 4 on it too. (I did the same thing at a different moment in the video but caught myself that time.) It's actually not easy to show this line must also have a 4 on it but here is one way you can do it: 1. Note that 9 must now be on the line in box 3 in r2 by sudoku. 2. Note that 1 cannot now be on this line in r2 as well. [This is a quite beautiful point. If you try and put 1 on the line with the 9 in r2 then it is either next to the 9 making a 10 domino or it will make the alternation along the line incorrect!!!] 3. This forces 1 in box 3 into r1. 4. Now look at r2c7. This digit can only be 4/6/9 as any form of yellow 2378 will create a 5/10 domino with r2c6! 5. But this digit also cannot be 9 because (and this is ANOTHER brilliancy from Phistomefel) the other two low digits on that Whispers line in box 3 would now be a 2/3 pair summing to 5! 6. It also cannot be a 6 because this would need a 1 next to it in r2c8 and we know the 1 is in r1 in box 3. So this digit is actually a 4. This forces a 4 onto the Whispers line in box 1 and the logic I did find can continue thereafter. Apologies everybody. Let me know if it might help if I made a short video to explain this.
Although I always love extra CTC videos, a pinned comment explaining the mistake works for me.
Yeah agreeing that a Video is not necessary. But pinning the comment would help. Thanks for the explanation and the beautiful solve today!
I watched the video and thougth to notice the error and found this pinned comment, good job! Not necessary to make a video on it in my opinion.
On 5.: I still have r3c8 as being possibly 4, which wouldn't cause the 2/3 pair summing to 5 problem. That would require a 9 next to it in r2c9 though, conflicting with the 9 we're supposing in r2c7, so it still effectively rules out the 9.
I think this catches it! Thank you!
I think you can be proud to have created a community where so many people react when you make an illogical step.
I see the words "phistomefel" and "miracle" on a movie-length video and I know we're in for a ride.
This might be the best comment I've seen in all my years on youtube
I agree and i also agree to Eminent Sharky as well
A movie lenght video... I ahd never thought about that and now it's making me question my life choices...
The restrictions on 4 in box 4 eluded you for great time after placing the six. then at 54:04 you placed the pencilmark 4's in box 1, straight up shouted X-WING! at the computer.
Cannot and will not ever be able to do what you do, and even keeping up with your logic or spotting something 10 mins before makes me feel so smart :') But the best thing is just to see you get so happy and genuinely touched by the logic and effort people put in their puzzels. You're a joy to watch
So there is now 4 degrees of difficulty in Sudoku: easy, medium, hard, and Phistomefel
Might I suggest 'ridiculous' as a fifth?
Comes right after 'hard'.
I want to hear Simon say “This puzzle comes highly recommended. It has an astounding ‘P’ rating on Logic Masters Germany.”
I'd say there are more: easy, GAP (generally approachable puzzle), medium, hard, monstrously hard, ridiculous and then Phistomefel.
I’ll alledge there’s more.
Level 1: Easy, Level 2: GAP, Level 3: Medium, Level 4: Hard, Level 5: Really difficult, Level 6: Monstrous, Level 7: Ridiculous, Level 8: Absolutely Ridiculous, Level 9: A level I call “what on earth is going on here”, Level 10: Impossible, and then… Level too insane to be confined by something as simple as a number: Phistomefel, the ultimate boss
C'mon it wasn't that difficult, I only did it in 3 hours, with intermittent breaks of course for my brain to rest so that it recover from overheating thinking about the whisper lines and negative constrains and my color scheme where yellow pairs with blue but not green which pairs with orange which can pair with blue but not yellow.
So yeah not that difficult at all.
Seeing "Phistomefel" in the title just makes me so happy every time I see it. I can't wait.
Agreed! Sometimes I tire of their use of SEO by titling their videos relevant to current popular search trends, and I'm always happy to see the authors of these wonderful puzzles featured more prominently (Even in this case when we know Simon already obviously fawns over this author incessantly)
I am so relieved he noticed the grey 1 at the end.
Me too
I'm pausing my watching of the video (at around 37:30) when Simon says that he has tears in his eyes. THIS is why I love this channel - not only because of the quality of the puzzles, but mainly because of the enthusiasm and genuine pleasure that Simon and Mark have in the beauty of the logic and the thought that goes into these hand-crafted puzzles. OK, now resuming my watch ... I am sure I will be equally impressed in the coming minutes of this video, but I had to pause now so that I could capture this thought.
24:12, simply the best epiphany ever witnessed on CTC.
I live for moments like 24:13. It brings me joy to see Simon’s joy when stumbling upon a great piece of logic! 🥰
Ditto!
It also proved that we in fact are closely related to... *monkey noises intensify*
Exactly, I love how he instinctively knows he stumbled upon something big, but then always takes a moment to realise what he has actually found
Definitely made me smile :3
rules should have been: 2 adjacent cells summing to 5 or 10 are marked with a V and X respectively, all X and V are given.
This would have sounded a bit more intimidating
Yeeeey I had the same thought, I would've loved that :D
And Roman 😀
Yes, I was thinking that too. The rule set is basically the V/X marking with a negative constraint, and there just aren't any Vs or Xs.
I honestly don't know if I prefer explicitly having that wording or just having it there but implied, with a nod to it in the title.
Yes, this would also explain the "roman" part of the puzzle.
Simon when solving: Tears of joy
Me when solving: Tears of terror
Phistomefel, you utter genious 👌🏽
@51:20, proving there's a 9 on the line doesn't immediately prove there's a 4 on the line. Takes a few extra steps to eliminate the 4: The 9 on the line in box 1 forces a 9 onto the line in box 3, and that prevents a 1 being on the line in box 3, forces the 1 into r1 of box 3, can remove the 1 pencil-marks from r1 of box 1. Now 4 can't be in r2c2 as it would be next to a 1. If 4 is in r2c3, there's nowhere left for 6 in r2. If 4 is in r2c1, that forces 1 & 6 in r2, leaves only a single low digit remaining in r2, the yellow 23, which must go r2c8 for the box 3 line to work. That must be surrounded by 9 and yellow 78, yellow 78 can't go next to the green 23, so r2c7 is a 9, r2c9 is the yellow 78. And now r3c8 has no fill. Can't be 1 as it's already in the row. Can't be yellow 23 as it's already in the box. Can't be green 23 as it's next to yellow 23 and would sum to 5. Can't be 4 as it's next to 78 on the line. So it's broken, and that proves the 4 you assumed on the line in box 1 is really there.
thx - I just was wondering how that works :-)
(Simon added a pinned comment about this.)
thank you this was bugging me
the last bit of logic that clears up the 7/8s & 2/3s is so beautiful. The "odd one out" hook-shaped whispers line coming back to be relevant just feels so satisfying (especially since my first thought at seeing the puzzle was: "that is different from everything else, it'll be important for disambiguating something important." my first instinct was to start there)
What an absolutely ridiculously good puzzle from Phistomefel and a solve of near-equal proportion, especially when combined with the very well written pinned comment. Just absolutely incredible. I have no idea how this channel isn’t huge. This channel deserves AT LEAST 1,000,000 subscribers, but I would’ve expected it to have double that by now. Stunning logic, cool ruleset (Anti-Roman? Perhaps call it Greek?), and yet another beautiful combination of one of the best setters in the world and one of the best solvers in the world. Bravo.
There's a neat way of thinking about the horseshoes at the start: Horseshoes never contain a 5 or two digits adding to 10, so they must have one 1 or 9, one 2 or 8, one 3 or 7 and one 4 or 6. This avoids having to enumerate all the cases by hand.
I was watching this with the captions on, and it was fun seeing the translations of Phistomefel's name. My favorite was "Vista my fellas"!
that reaction at 24:10 is just pure honest joy :) happy to see people enjoying what they do
Absolutely the most sublime final disambiguator of a puzzle I have ever seen.
Staring at an almost completed grid with nothing undone left but 23's and 78's in every box and going "I know this must resolve, but how?" and then the resolution was just amazing. And it's not through an added element, like a given digit or an inequality sign, or a stubby thermo -- just brilliant. Honestly from the very beginning I thought "Hmm, whispers puzzles usually have to have something to disambiguate hi from low, but there's nothing here but the lines. How odd."
When I placed the 78 on the whisper line in box three I thought it might be significant that I couldn't determine which flavor of 78 it was (my Spidey sense was tingling as Simon would say), but it was even more beautiful than expected. What a finish. Just over 2 hours for me. I didn't make the unjustified leap Simon did to place 4 on the line in box one with the 9, but even my best attempt at self delusion cannot convince me that made up for the 40 minute difference in solve times! In a just world this would have at least 10 million views.
"Self praise is no praise".
Okay then Simon: I'm proud of you!
I didn't even bother trying to do this one even after watching the break in. A masterpiece.
Rules: 03:09
Let's Get Cracking: 04:29
Puzzle Solved: 1:22:50
Simon's time: 1h18m21s
What about this video's Top Tier Simarkisms?!
Phistomefel: 8x (00:20, 00:39, 01:00, 01:10, 02:38, 26:44, 1:04:27, 1:24:30)
And how about this video's Simarkisms?!
Beautiful: 12x (27:11, 35:42, 36:30, 36:33, 44:00, 49:52, 55:36, 55:36, 55:44, 1:17:09, 1:20:42, 1:23:25)
Obviously: 12x (01:43, 06:13, 08:09, 10:03, 10:12, 19:21, 26:15, 34:54, 35:38, 35:53, 59:34, 1:11:42)
Sorry: 9x (10:07, 32:22, 41:56, 51:47, 51:47, 51:47, 52:48, 55:12, 1:04:09)
By Sudoku: 9x (30:50, 31:06, 35:39, 37:02, 44:57, 59:01, 1:01:20, 1:12:54, 1:19:31)
In Fact: 8x (00:25, 08:41, 11:40, 44:55, 52:35, 1:10:26, 1:12:41, 1:19:31)
Wow: 7x (24:19, 34:22, 40:10, 46:31, 1:03:29, 1:13:07, 1:14:44)
Good Grief: 6x (13:10, 38:15, 49:34, 49:52, 1:00:16, 1:15:07)
Hang On: 6x (05:22, 28:58, 29:00, 1:06:47, 1:09:52, 1:21:57)
Progress: 4x (28:34, 31:17, 45:25, 1:07:52)
What on Earth: 3x (21:12, 31:25, 1:00:06)
Goodness: 3x (52:48, 1:09:07, 1:10:56)
The Answer is: 3x (12:14, 27:59, 1:01:26)
I Have no Clue: 3x (01:36, 31:31, 38:34)
Clever: 2x (26:39, 40:10)
Approachable: 2x (01:59, 02:18)
Stunning: 2x (1:22:58, 1:22:58)
Useless: 1x (1:00:54)
What a Puzzle: 1x (1:22:54)
Naughty: 1x (28:16)
Break the Puzzle: 1x (09:19)
Fascinating: 1x (08:51)
Incredible: 1x (1:23:46)
Extraordinary: 1x (02:51)
Elegant: 1x (1:23:22)
Ridiculous: 1x (26:48)
Deadly Pattern: 1x (1:15:05)
Discombobulating: 1x (1:24:24)
Shouting: 1x (52:51)
Surely: 1x (1:09:41)
Most popular number(>9), digit and colour this video:
Ten (42 mentions)
Two (148 mentions)
Green (86 mentions)
Antithesis Battles:
Low (19) - High (18)
Even (5) - Odd (0)
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!
"I know two things about German Whispers lines" should be added
How many times does he select/clear/reselect the same cells over and over and over?
@@BB1-l2k Inspiring Sand is a bot, not Rainman!
Shouting tends to be two different ones - You Are All Shouting At Me (for missing logic or the obvious) Shouting(going on) for when the kids are on holiday and playing downstairs or in the garden
There was a Cooking With (Proverbial) Gas. Presumably the price of Gas has gone up so needs the proverbial !
In my mind, I'm imagining a scenario where Phistomefel isn't actually a mad genius. Instead, he's just incredibly lucky. Each time he wants to make a new puzzle he draws a couple of lines, randomly assigns a ruleset, job's a good'un.
In this reality he's baffled by his success, and is constantly worried that one day he'll draw something wrong and the puzzle will consist of only deadly patterns.
🤣
sounds like ButteredSideDown xD
That's King from One Punch Man.
A sublime work of genius. Phistomefel doesn't just create magnificent puzzles but new discoveries around patterns (which we, ably guided by Simon, are allowed to discover). How such visual simplicity leads to such an extraordinary line of logic leaves me gobsmacked.
At 1:04:38, you could resolve box 9 as the 2,3,4 are all ruled out of the whisper line. Since there has to be a low digit, you can place the 1 on the line and forcing the 9 into rows 7 and 8 by the XV restraint. This would get you those numbers in box 7 as you had suggested might be possible
"Don't get any ideas constructors out there!"
Someone probably just thought "Challenge accepted, I'll make one of the digits on each German Whispers Line a secret 0 or 10, which a 5 can be next to."
Nice.
I was thinking more along the lines of digits must be between (minus)9 and +9. With the row, column, and box totals being +/- 35...
[Edit: RUclips seems to hate negative numbers in comments. How self-protective. 😉 ]
Or a Killer Sudoku where one cell per row, column, and box is negative
I'm thinking that the Schrodinger Cell rule set with the ten digits might be well suited to breaking German Whispers for that puzzle.
@@DanielHShead Every cell contains the digits 1-10 (plus or minus). The sign may be different vertically and horizontally.
What kind of hell have we unleashed on sudoku?
I'm sorry, Simon and all. But I think this will happen.
I still need to trace through the whole "wrogn" thing where I'm fairly sure a flippant remark like this led to it being actually made into a real puzzle.
OP is right. The puzzle setters need a challenge too. And a word to the wise; they are vastly more intelligent than we are...
the absence of the comma in the quote really confused me and made me start thinking about who constructs ideas
As always the sudoku setter master is able to use a simple ruleset and produce an extraordinary and unique sudoku. I managed to solve this in exactly 1 hour and I am happy with that!
In some weird way, Simon makes me feel smart. I find a number or even just understand the logic during the solve and feel proud. Don't know how you do it Simon. :)
When he's banging out such intense logic over and over it feels good to be up to speed even if for a moment
I feel the same except for when he starts doing odd versions of SET - some of that is still very confusing for me
37:39 “Flaccid flashage” 37:43 “Maybe I should give those some sort of flaccid flashage as well.” Simon coming us with new terms left and right! 😂
I loved it at 28:30 when Simon jokingly says "We've practically done the puzzle!" when there actually almost an hour to go yet.
Just under 2 hours, although I did have some distractions along the way. This was an absolutely BRILLIANT puzzle. As Simon would say, it's "classic Phistomefel" in every way. Absolutely loved it.
Wow! Very satisfying to solve it unassisted. Hit a brick wall after three hours but after a good night's sleep woke with fresh inspiration and finished after another hour. Hats off to Simon or anyone who can do this in less than two hours. Crazy puzzle.
I was able to solve it, I think it's the first time I could tackle such a big beast! It took me some more than two hours. Yet one thing that helped me a lot, at my own pace, but I believe would have been helped Simon to do it faster was to pick a color for each domino tile value (so, all but the 5). I picked "friendly" colors for the dominoes members, hence yellow/green and blue/magenta were the high/low for the 78/23 dominoes, red/orange and black/gray for the 61/94 dominoes. By combining colors it became way easier to scan the grid and find matches and mismatches. Another thing I am doing when pencilmarking, is to use the 0 as a placeholder for "and something else", so it help me make partial pencil marks while keeping track that there are still missing digits to ponder. So, by writing in the cell center "092" I know the 92 are candidates, yet not the only ones even when I still didn't figure out the others (I guess it'd be great to have an unrestricted pencilmarking, allowing characters and other symbols, much like regular expressions to express sets of alternatives or to exclude values).
Be proud, be very proud. A brilliant (and unsolvable for me) puzzle and a wonderful solve. Thank you.
This puzzle is brilliant. I love minimalist constraints like this. The emerging logic with 2-7 and 3-8 pairs propogating through the grid was quite satisfying to discover. Took me over two hours, and I only got unstuck around the 40 minute mark.
I had to( in a way) biforcate around how the horse shoes worked I suspect there is a way to figure it out simpler then the path that I took. Loved the puzzle took me two days with a break. But so fun can't wait to watch the video.
What an amazing puzzle !! When Simon has to solve a mini sudoku before even beginning to solve the entire sudoku, it says something profound about the puzzle itself. Loved the solved as always !!
50:35 Did I miss an explanation on why having a 9 on the whisper line requires a 4? A 4 requires a 9 but I'm not immediately spotting why (23)-9-(23) or 9-(23)-(78) doesn't work.
Simon added a comment about this 5 minutes after yours
Yeah, Simon has done it again.
The way to prove this is to first notate the 9 on the Whispers line in box 1 (that we've just proved) and then notate it on the Whispers line in box 3 (top three cells of the line).
Now regardless of where you place the 9 on the Whispers line, a 1 couldn't accompany it since it can't sit next to it (10-sum) nor have a square in between them since it breaks the high-low principle of the Whispers line. Therefore, in row 2, 1 can only be placed in box 1.
At this point if we assume 4 wasn't on the Whispers line in box 1 we'd have to place it in one of the three cells above it in the same box. This gives us a 1-4 pair in box 1, leaving the central cell empty because of the 5-sum rule, and as a result, a 6 lives in the top part of box 1.
Now, in row 2, we have relatively placed 3/4 low digits, so on the top part of the Whispers line in box 3 we can have at most one low digit and to abide the high-low principle it must be in the center, ie the central cell in box 3. As there's a 1-4 pair in the row this cell is either 2 or 3.
Again on the same Whispers line, by the high-low principle, the cell directly below the central cell must be a low digit. Better yet it must be a 4 in order not to create an orthogonal 2-3 pair which breaks the 5-sum rule.
All the pieces are there and the punchline is you can't place a 6 in box 3.#
There's a 4 on the Whispers line in box 1.
this is one of the best and beautiful solve paths I've seen (working through this in vaguely chronological order, a year behind 😂). superb that it gets coloured completely then that last whisper resolves it. phistomefel is a complete genius
It took me nearly two hours (I clocked in at 1:43:39, but it was probably a few minutes beyond this), but I was able to tame this behemoth.
Stunning ... simply stunning!
Nah
Wow, what an amazing puzzle! Thank you for sharing this with us.
It took me about three hours to solve it myself. But the joy upon finishing... Wow!
Great finish with that one rule disambiguting the remainder!
Good job Simon!
Thank you Simon for sharing your thinking with us! What a journey!
One of Phistomefel's best! Sometimes they're way too hard, but I only needed a few dozen hints from Simon this time. Great solve, Simon!
I usually don't even look at videos that are longer than 45 minutes - but this was a treat from start to end, and well worth the time!
The way that you figured out that there was a forcing sequence with the horseshoes was nothing shy of brilliant. Just noticing that the horseshoes only had four potential configurations was more than I ever would've gotten when attempting this puzzle.
Finally took the time to watch this in its entirety, and WOW. Absolutely amazing job - once more - by both Phistomefel and Simon. Just excellent.
I watched and marveled. I got that it had to do with constraints in the horseshoes but gave up before working through them. I appreciated Simon writing down options. I will do that next time and maybe advance a bit further.
Moment of appreciation for Simon’s ability to find and be moved by beautiful puzzles
currently in the middle of replaying all of the sudoku apps:)) one of my favorite pastimes now a days is listening to creepypasta readings while solving sudoku puzzles via cracking the cryptic apps. hope u guys are planning on more updates/puzzles/apps for the future because im really enjoying them:D
Phistomefel should have called this XV Whispers with the XV constraint listed in the rule set along with “All instances of orthogonal digits summing to 5 or 10 are given.” And then Simon would be even more incredulous with NO XVs and just negative constraints! Very powerful and yes, this was just a popcorn episode for me.
I really think this is one of the all time great puzzles. The combination of simple rules, sparse grid, and challenging logic start to finish. Extremely elegant and unique.
First time through I solved thanks to (a) an egregiously lucky error and (b) trifurcation (lol) on r2c7. On watching the video, Simon's early steps were much cleaner than mine (as usual). I do have a quibble at 50:04, I don't see how he's proven there's a 4 on the box 1 whisper line, but the 9 is certainly proven and that fixed my solve. Reworking from that point it puts a 9 on the whisper line at r2c7..9, and you can easily resolve which cell it's in.
Many thanks to Phistomefel and Simon.
Just thought I'd point out he actually has a pinned comment explaining that mistake he did if you wanted some more information on it!
@@MinecraftTheCreators Hmm I think I made my comment on an un-refreshed copy of the video, I didn't see the pinned comment at the time, sorry for the duplication.
Haha ur fine! Figured it was something like that, just wanted to make sure you didn’t miss it 😄
69 minutes exactly here. I found that really tough but then that's to be expected given the identity of the setter. I enjoyed it though. Amazing puzzle at first glance, my initial reaction was "How on earth am I meant to start this?"
This video deserves a cinema trailer.
Like this:
*Dramatic drums*
Bass voice:THIS WINTER
...
Simon:Oh dear
...
Bass voice:From the creator of the most creative puzzle
...
Simon:God grief
...
Bass voice:Phistomefel
...
Simon: absolutely genius
...
Bass voice: with the famous puzzle cracker Simon Anthony
...
Simon: we've broke the puzzle
...
Bass voice: GET READY TO BE CRACKED
...
Simon: let's get cracking
...
Bass voice: now on RUclips!
:D
50:35 Got scared here. Your proof said that the 9 has be in the line, but the 4 could still not be in it. It could be 3-9-2 still. Or 8-3-9 and others.
Luckyily it turned out right in the end!
I had the same thought. Is there some reason why there had to be a 4 next to the 9, or did Simon just get lucky?
@@zoicon5 He got lucky. See Simon's comment pinned above 📌, and my reply.
No day is complete without Simon waxing poetry about Phistomefel. Always makes me smile 🥰😂
The fact that green and yellow were disambiguated as the finale extravaganza, chef's kiss
"The 9 and the 6 form a nice relationship here" had to rewind the video and make sure I'd heard that right the first time 😂
Opened up the puzzle to attempt it, like I usually do, and immediately closed it and said "lets just watch today"
A video of Simon just reading off names? … I would watch that video tbh.
I’m fairly new to this whole channel and deeper sudoku puzzles. I absolutely LOVE you guys! Thanks for opening this new world to me ❤️
When you mentioned this puzzle a few days ago I set myself the challenge of solving it before you posted a video of it. I definitely needed the head start, but got through it. Brilliant puzzle as always.
Wow! What a Phistomefel puzzle! The interaction of the 4-cell German Whisper rings and the anti-XV rule set is just stunning, although it took me an hour to figure it out! But even afterthat, there are still more and more logics in it and every time I spot the beauty of them, I just feel "Wow, how can sombody come up with this?!" Finally I used around 2 hours to solve it. I haven't watched the video yet but I am looking forward to the solving of Simon. (I am from Hong Kong, so please forgive my bad English.)
Thank you!
At 38:52 I spotted a missed song opportunity: "Green can't live next to yellow 2 or 3" (sung to Yellow Submarine)
That fits incredibly well. :)
Hooray, tick of approval from the maestro himself! Now I only need to work out the rest of the lyrics 😊
The last rule could have been written as: "Digits joined by an X add up to 10. Digits joined by a V add up to 5. All Xs and Vs are given!" :D
Great idea for an april fools puzzle!
And that is why it is Roman
Agree. Also, I think there does need to be an agreed way of writing rules. Standard sudoku rules apply, standard Thermo rules apply, standard VX rules apply - all XV's given etc etc
m I think Mark did such an XV puzzle last year sometime.
That’s a fun one. You still need the word “orthogonally” in there for clarity though.
I solved it in just under 100 minutes. That's the best puzzle I've seen in a long time.
Woohoo! I love it when Friday night is movie night! Love the "popcorn videos" lol ❤️🌟
1:15:00 69 X-wing ruling out the nines in box 7! Counting the seconds when you notice it :)
Always enjoy watching your sudoku solving.
There's more beautiful logic appearing out of thin air in this puzzle than most contain by force.
24:20 the perfect description of this channel
This is the most beautiful sudoku I have ever seen. Including many I have watched from this channel.
I didn't even had a start when I tried this puzzle so I religiously followed your logic on this one... But I had an interesting thought at 1:05:22 which is the following:
At this point I was wondering "how can you tell appart which color is the 3-8 pair and which color is the 2-7 pair". And o figured out that the only way was to use German whisper's line rules, and to have a green and yellow cell next to each other on a line (this was because no 2,3,7 or 8 were placed and the only rule playing on numerical value was the whispers line). And as they can't be orthogonally connected, they needed to be neighbors on the line in box 3. So if r3c8 wasn't green, the puzzle wouldn't have a unique solution, which isn't the case. Therefore, r3c8 was green 7/8 and, since it is next to a yellow 2/3, it was an 8.
I really like the logics involving the unicity of the solution in a sudoku, so I was proud of that one.
Astonishing puzzle; lovely way to spend the early evening. Really enjoyed finding the break-in here. 1:18:16.
This sudoku is simply stunning! It turns out that the start doesn’t even require you to guess the parity of the whisper lines, you can just use colours and logic to isolate the options as follows;
There are exactly 2 ways of making the ‘horseshoe-shaped’ German whisper lines work if you ignore the combinations of 2,3 and 7,8 pairs (4 - 9 - 23 - 78 and 6 - 1 - 78 - 23). Since we know by sudoku that the whisper lines in boxes 4 and 5 are different (the 4,6 pair see each other in row 5), the 2nd and 3rd cells respectively on each line must be of opposite parity and appear in the middle of the line (though we don’t yet know the order). This is particularly powerful for the 1s and 9s, since the 1 or 9 in box 4 is forced into column 6 of box 5, meaning the whisper line in box 2 must be the same type as the whisper line in box 5 (both must contain a 4 and 9 or a 6 and 1). By similar logic, the 1st and 4th cells on the whisper lines cannot be in the centre of the horseshoe, so the 4,6 on the line in box 5 must go in the bottom leftmost cell (it will see the same digit in box 2 otherwise) and this determines the order of both lines (remember that the 4,6 pair in row 5 must be kept apart in order to not create a domino adding to 10). Now we can colour the 2,3 and 7,8 options. The cells on the whisper line in box 5 must be of different parity and cannot add to make 10, so we can colour them red and yellow respectively (we are treating red and blue as one of the pairs adding to 10 and yellow and dark grey as the other). The important step is to realise that the 3rd cells on the whisper lines in boxes 2 and 5 must share the same parity. So we may not know exactly where the 3rd cell on the line in box 2 is but we do know its colour (blue and yellow are both opposite parity to red, so it must be dark grey) and that it appears in column 3. This places dark grey in row 6 column 4, since it cannot go next to yellow (they would add to 10) and the fact it is of opposite parity to the 3rd cell on the whisper line in box 4 makes that cell blue. Now blue only has one place to go in box 5, as it cannot go next to red (again, it would form a pair adding to 10) so must be next to yellow. But we know that yellow and blue are the same parity (as red and dark grey are the other parity) so they cannot be from 2 and 3 (or else the domino would add to 5) and thus must be from 7 and 8, which fixes the parity of the whisper lines in boxes 2, 4 and 5.
Hopefully I didn’t mess up anything in that explanation. A genuine thanks to Phistomefel for an incredible idea that made for an amazing solve. :)
52:54 "You've all been shouting at me for about a minute and a half haven't you?" Ok, first of all I don't know how I got so into a video about solving a sudoku that I was shouting at the screen and second of all I don't appreciate being called out, Simon.
This really looks like a miracle. New ruleset and stunning logic from start to finish 👏.
I used different colouring for 23 and 78. I believe it makes everything more familiar and hence easier to grasp (at least for me):
green 23 ➡ green 23
green 78 ➡ blue 78
yellow 23 ➡ yellow 23
yellow 78 ➡ purple 78
The logic of this puzzle is just mesmerizing. Fantastic puzzle and an equally fantastic solve!
And once you see the logic, it isn't even mad genius logic. It's simple beautiful logic. Every time it happens you say oh yes of course, instead of... WTF
What an amazing puzzle.
A clean way to get initial digits is to introduce 4 colors for pairs that sum up to 10. You can then prove that U-shaped lines consist of 4 different colors - since each element must be different than its two neighbors (to avoid 10 sum) and different than last one, since whispers would make it same digit.
I really struggled with putting digits on the top right line - both with putting 9 there, but also later with 4.
Funnly enough - once you have 49 there, you actually can prove 78 is yellow (54:54, after conclusion from 56:30). You need to consider color of 23 on the top left line - if it is green, you will need to put yellow 23 and green 78 in the top row of that region; with neither being in the middle (10 sum) they will collide with 6. That 23 being yellow forces green 23 as a neighbor of 78 in question.
(Would be nice if I noticed that before incorrect conclusion that it is green and reaching a paradox)
Yet another brilliant epic. I had to have a separate screen with the horseshoe possibilities as couldn't keep it all in my head, glad to see Simon doing the same.
I solved Balance Loop the other day without too much trouble, but I looked at this puzzle, worked out a little bit about the horseshoes, but just couldn't get the break-in. Thank you for the solve. I repeat your self praise to you that it may gain value, and I ridicule you for trying to put a 4 in the middle of a German Whispers line.
Sorry, I do want to do the usually comment section of some bad logic:
You mentioned at the end of the video that "Self praise is no praise at all." Out of all that, you can't get yourself some self praise?!? Nope, not logical. Please unwind and give yourself the praises!
But really, be proud. This was an amazing solve of an amazing puzzle, by an amazing constructor. ALL THE SELF PRAISE!!
That's all. Thanks for the movie before bedtime :-)
Way to go Simon!! Brilliant puzzle and even more was the solve!!
Just love watching you solve these puzzles. Especially your reactions when you find something. 👍
Simon: brilliant logic, explaining at the start how 4 and 6 can only be at the end of the line.
Simon, 40 minutes later: wondering where would the 4 and 9 go on the line.
If this isn't me 90 % of the time, idk what is. The loss of focus is too real.
EDIT: the 'why is my brain not working' part is also very relatable, don't worry Simon, you're a genius anyways, losing focus for a moment isn't your fault!
I did the last step a bit earlier and different: since r2c6 and r2c9 are green and yellow 23s respectively, and both connect to green 78s on a whisper line, green 78 has to be 8 to match whichever of those is 3. So I had my 2378s sorted out long before finishing the rest of the puzzle.
Incredible puzzle and solve as always.
I'm days late, and self-praise is indeed no praise, but I was particularly happy at being able to solve this one, however slowly. I just loved the series of epiphanies as the logic unfolded from the 46-19 interactions to coloring the 2378 dominoes.
I managed to do all the hard logic somehow, but failed to see 1 in r3c5 forcing 4 to be at the top...
Well, I'm fascinating of brilliance of the installation.
I wonder how's the author come up with such an idea!
Simon, great job, congratulations!) And thank you for bringing this to me :)
What a delight of a puzzle, thanks Phistomefel! And Simon, my rusty brain does a calisthenics class watching you solve 😄, whilst having fun! Thank you!
52:50 I was indeed shouting at you for about a minute. I'm glad you heard me eventually.
Just got to 24:05. Had to re-watch it twice just to appreciate Simon's reaction.
Priceless. 😄
1:24:57 "... and I'd love to know how many of you finished it" - bro, whenever I see a phistomephel puzzle I know that I'm not even going to attempt solving it. I just get the priest into my room to exorcise it and then I get the popcorn and watch the movie
So glad that grey 1 got resolved in the end! It was staring at me the whole time 😂
4h20m. Similar path to Simon's but I used four colors for 23/78 instead of two colors and I think that made it harder for me to spot how box 3 was different from box 5 at the end. Very hard but very satisfying puzzle.
This was a lot of fun, as always with Phistomefel. Using distinct colours for the 2/3/7/8 worked well for me, as I find "yellow 23" a bit cumbersome - this also made filling in the final digits easier. I made a stupid error towards the end but then when I did the final fill-in, one of my whisper lines was broken. Easy enough to rewind and spot the error.
At 51 minutes, what's the justification for the line in box 1 having *both* 4 and 9? I think all you proved was that it needed 4 *or* 9 (which easily leads to needing a 9, but 2,9,3 for example looks fine at that point).
Was thinking this too, can't tell if I'm missing something or he got very lucky that the solution happened to have a 4 on both those lines
Yeah i noticed that too, i think he got confused thinking that a 9 on a line means a 4 has to be there too (when it's actually the other way around)
I paused the video at that point to come and ask the same question.
Simon does address that in a comment - the comment was posted after your comments.
Agreed; I'm trying to see the logic there too.
Okay, have finished the puzzle and now its time to watch Simon get lost in the devil's labyrinth.
German whispers are now my favourite variant; Oh and I shall derive immense joy if Simon chooses the similar colour scheme to resolve the whispers.
(Edit: Brain - Immense joy received)
50:40 - Why can't 9 be on the line with 23 on either side? Or any of the 8/3/9, 7/2/9?
It can‼ See Simon's comment pinned above 📌, and my reply.
@@Paolo_De_Leva Yeah, thanks, but I posted that question before Simon's reply :P
@@Bonar09 Of course. That's what I assumed, and the reason why I warned you.
I solved my first Phistomefel puzzle a few days ago (and no it wasn't the 1 star one haha) and i'm very proud of myself, i saw this puzzle on LMD and i was amazed by the minimalism in the grid, can't wait to watch.
D stands for Germany, right?
@@LukeSumIpsePatremTe Yup, Deutschland
The rules should have explained X, V and ended with all Xs and Vs are given. I think that would give you a moment of "that's useful" which immediately turns into "oh no" once you look at the grid. :D
That is hilarious - feels more like how the rules might have been phrased if it were a Zetamath puzzle, perhaps!
I think that wouldn't work for many reasons
I think this would only work if you had seen an XV puzzle before. If this was the first XV puzzle I'd ever seen, I'd just be convinced the grid wasn't loading correctly in my browser and move on.
@@RichSmith77 don't know if you would be considered lucky or unlucky that the first XV puzzle you see is by Phistomephel
@@xvnz 😁
Somehow I got you to read my mind through a time machine. Yes I was thinking that you told me the 4 can't go on the interior if a whisper line.
30:26 “And now we have a ‘GRID OF PURITY’”. Sounds like the next Phistomefel puzzle to me
Simon is a catchphrase factory
This is just a beautiful puzzle. No idea how such a thing gets set. Wondering whether Phistomefel has been studying Simon's solving techniques (and/or psychology). Simon, I find your solving compelling - sometimes I see things ahead of you, but the consistency with which you find helpful techniques (eg the colouring in this one was non-standard) is beyond my capability. I learn something new every time.
Still watching it, but why must the whisper line in box 1 contain a 4? I see it must contain a 9 but not necessarily a 9 AND a 4 (at least without going into any further logic)
A mistake. See pinned comment from Simon.