The New York Times Hard Sudoku: The Most Important Trick

We "live-solve" the New York Times "Hard" Sudoku on 31 Jan 19. Simon discusses the importance of 3x3 scanning and demonstrates how this cracks the puzzle.

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[ridefast]

Thank you so much for showing these solves 'warts-and-all' - it helps me know that its not just me sometimes! I found my first X-wing recently, what a buzz. Its funny how I understand even the more complicated techniques while being shown them, but all my tools evaporate as soon as a real puzzle is in front of me! I hope this is inexperience rather than old age!!

[grenvillephillips]

Another useful tip to keep me going through my slog amongst the foothills of Sudoku competence. Now, if I could only remember them.

[JohnRandomness]

I admit that I didn't recognize the obvious triples with row 8 and box 7, and that made me take longer and work harder. However, I think that disciplined(?) corner-pencilmarking and finding and center-pencilmarking cells with only two or three possible digits will gradually reveal and lay bare a hidden triple for all to see and observe.

[bluestar]

Thank you this was good. I solved this puzzle previously and saw the triple quite late. It took me more than 30 minutes. I guess I normally work on rows and columns and then look for patterns. Perhaps I need to look for patterns as you said first and then work through rows and columns next. I'll try this and see if I get to the solution faster.

[sandpiperbf]

You make it look so easy, but I still struggle to solve these without center pencil marks. Even then I can get stuck.

[johnoliver]

Great video. Do the NYTimes puzzles ever use such things as Xwings either normal or sashimi, swordfish, Wwings etc? I’ve spotted them occasionally.

[barbaraclampin]

I'm struggling to progress beyond Medium. I can't understand at about 7.48 - re the 1689, you say the 9 must go in block 4? Please excuse me being dense!

[gerasimos]

Does this puzzle have a uniqueness problem? You can reverse 5 and 9 in rows 1 and 3 i think.

[Ensivion]

@8:01 couldn't the nine go in row 2 column 2 instead, then the other nine could go in row 6 column 5

[chookingvid]

I solved it without the trick in the beginning, but I took longer.

[yzwrvbf]

At the very beginning in row 1,  the 37 pair can only go in r1c1 and r1c8

[brianlutz]

still no luck solving a hard sudoku ... i get about a 1/4 of the way through and hit a wall ... every stinkin' time

[DaveGeelen]

You didn't use much logic at all idd :D
So funny to see you struggle at very easy things, while you are 100 times better than I am at this :D
Finding the 9 in the bottom middle box, I see immediately that in the center box, 9 can only be on the left, and so on the upper middle box, the 59 are solved :D
And that took you like 30 secs :D
But the very hard things I don't find :D and you make that seem easy
Crazy how minds can be different, and even reality is different for everybody.