I enjoyed your explanation of the wing. It was fun for me to see you 'stuck' on occasion. I'm working thru the pack you provided as well so I'll be tuning in for them.
I saw that I did this puzzle before, although I didn't remember it. I did it again. It took me a long time. I found a finned swordfish when not-quite-Snydermarking 1s. Apart from limiting block 5's 1s to three cells, it gave me a 6 long after I'd forgotten it -- it would have been a 16 cell. The finned swordfish seemed like an accident. The only other advanced procedures I found and used were an XYZ-wing in 789s, which later turned into a Y-wing. The rest was simply noticing things, such as a single digit. The end featured numerous 79 pairs which I decided to color. 14:50 R5C4 lost its 1 with the finned swordfish, and is now 6. You also get a pointing pair in 1s in row 4. 16:30 At one point, I thought I had a deadly pattern in 79s, but fortunately, the cells were in four different blocks.
4:28 For your explanation of the XYZ-wing, pincers don't have to be in the same box as the pivot, they just have to individually see the pivot (same row, column, or box). Since r2c4 saw both pincers the 9 could have been eliminated from it earlier.
You are thinking of the Y-wing (sometimes called an XY-wing or bent triple). The XYZ wing has the shared candidate in the pivot as well (in this case, the 9), which means the cell needs to see all three cells in order to have the shared candidate eliminated. You can see that if you fill 9 into r2c4, it doesn't break the XYZ wing. It sets the pincers to 7 and 8, and then the pivot becomes 9. This would eventually break because it's not the solution, but the XYZ wing is fine with it. If the pivot was only 78 and not 789 like what happened at 9:31, then it is indeed the way you described and you can see I did the elimination of r2c4 then.
Way cool, love this addition to the channel. After your excellent presentation of the "XYZ Wing", my solve collapsed -- although it took me a total of 45 minutes. Interestingly, I saw those bivalue cells involving 9 early on and even colored them. Sadly, I didn't have the "XYZ Wing" pattern and so I didn't know what to do next. I then spent about a half hour of fruitless pencil marking and coloring. It took me about 15 minutes longer to solve the puzzle once I had the "XYZ Wing". Kudos for a great enhancement of the channel.
Very excited to see this series. Unfortunately I didn’t spot the XYZ wing, but somehow managed to eliminate a bivalue from box 4 with a kind of chain which did solve it for me. Thanks for explaining the logic of the actual solve path. Will look forward to the next puzzle!
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This series is invaluable, learning loads so please keep them coming. Just need to apply and recognise the techniques when solving
I enjoyed your explanation of the wing. It was fun for me to see you 'stuck' on occasion. I'm working thru the pack you provided as well so I'll be tuning in for them.
I saw that I did this puzzle before, although I didn't remember it. I did it again. It took me a long time. I found a finned swordfish when not-quite-Snydermarking 1s. Apart from limiting block 5's 1s to three cells, it gave me a 6 long after I'd forgotten it -- it would have been a 16 cell. The finned swordfish seemed like an accident. The only other advanced procedures I found and used were an XYZ-wing in 789s, which later turned into a Y-wing. The rest was simply noticing things, such as a single digit. The end featured numerous 79 pairs which I decided to color.
14:50 R5C4 lost its 1 with the finned swordfish, and is now 6. You also get a pointing pair in 1s in row 4.
16:30 At one point, I thought I had a deadly pattern in 79s, but fortunately, the cells were in four different blocks.
4:28 For your explanation of the XYZ-wing, pincers don't have to be in the same box as the pivot, they just have to individually see the pivot (same row, column, or box). Since r2c4 saw both pincers the 9 could have been eliminated from it earlier.
You are thinking of the Y-wing (sometimes called an XY-wing or bent triple). The XYZ wing has the shared candidate in the pivot as well (in this case, the 9), which means the cell needs to see all three cells in order to have the shared candidate eliminated. You can see that if you fill 9 into r2c4, it doesn't break the XYZ wing. It sets the pincers to 7 and 8, and then the pivot becomes 9. This would eventually break because it's not the solution, but the XYZ wing is fine with it.
If the pivot was only 78 and not 789 like what happened at 9:31, then it is indeed the way you described and you can see I did the elimination of r2c4 then.
Love the advanced series (in addition to the hard NYT ones)!
Way cool, love this addition to the channel. After your excellent presentation of the "XYZ Wing", my solve collapsed -- although it took me a total of 45 minutes. Interestingly, I saw those bivalue cells involving 9 early on and even colored them. Sadly, I didn't have the "XYZ Wing" pattern and so I didn't know what to do next. I then spent about a half hour of fruitless pencil marking and coloring. It took me about 15 minutes longer to solve the puzzle once I had the "XYZ Wing".
Kudos for a great enhancement of the channel.
Very excited to see this series. Unfortunately I didn’t spot the XYZ wing, but somehow managed to eliminate a bivalue from box 4 with a kind of chain which did solve it for me. Thanks for explaining the logic of the actual solve path. Will look forward to the next puzzle!
Great series. Learning a lot!
Glad to hear it!
Well, I got to admit that this one I couldn't solve at all!
I'll try bifurcation, but I feel like cheating by doing it.
I hit a similar barrier. These hand-crafted puzzles are marvelous because they really are impenetrable without knowing the "key" to unlock the puzzle.