The Easiest Advanced Techniques in Classic Sudoku

Here's where you can learn about X-Wings and Y-Wings, the easiest techniques after looking for singles and pairs etc.

Classic Sudoku: 1-9 appears in each row, column and 3x3 box.

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Tim McCaskey (Guitar) or Lucy Audrin (Piano) or Riffclown plays Mozart's Sonata no 16 ("Sonata Facile")
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Hi! We're Simon Anthony and Mark Goodliffe, two of the UK's most enthusiastic puzzle solvers. We have both represented the UK at the World Sudoku Championships and the World Puzzle Championships. We're also "cryptic crossword" aficionados. Mark is the twelve-time winner of The Times championship and Simon is the former record holder for most consecutive correct solutions to The Listener crossword. We hope we can help your puzzle solving while also introducing you to some of the world's best puzzles.

Thank you for watching!
Simon and Mark

[JasonPeltier]

That was really cool. I would love more targeted instructional videos like this.

[Davidgeification]

For a simpler final step after 17:05, there is an additional y-wing hinged on r4c2 with r4c4 and r6c3. Whatever number you put in r4c2, you get a 5 in either r4c4 or r6c3. Both cells see r6c4, forcing a 5 out of the box and giving you a 9.

[Babs]

This is great, while I think some people enjoy Marks videos for his swift solving, I really enjoy him taking his time and explaining his process. I would love to see more of this style from Mark, especially on puzzles with a range of difficulty

[longwaytotipperary]

While I love watching Mark & Simon battle the setter geniuses with charm and humor - I originally found this channel when I was looking for techniques to solve my own (lesser) formidable puzzles. I very much appreciate this and other puzzles that help me on my path to greater solving ability. Thank you, Mark!

[elevensalor]

I know this is one of the easier puzzles on the channel, but it was still the first I was able to solve without watching, so I am really proud of that! Thank you for helping me improve with every video!

[TheNewAccount]

Great puzzle. For the very end there is actually a trick that Simon showed years ago: If you have a puzzle where every remaining cell has two candidates and only one cell shows three, than you can figure out that 3-possibility cell: You need to look for the one digit that is shared in the box between all three cells (in this case 5) and that is the one that needs to go into the 3-possibility cell.

[angartsnirex]

I've been loving sudoku for many years now, maybe about 16yrs since i saw it and learned it. But it's just now i am learning that there are advance techniques like this lol loving this channel so much

[LetterheadStudios]

17:15 is the BUG +1 Principle. If you have nothing but pairs remaining and 1 triple, then the triple must be equal to the number in that cell that appears three times in the intersecting row, column, and box.

[ayannababii]

Omg I have never been able to figure out X-wings and Y-wings until now. And I've watched a lot of videos about them 😂 this was very useful!

[themorebeer]

I learned to look for 'bent triples' when scanning for Y-wings. 45, 57, 47. They always take the form of a triple, and can restrict any cell that is seen by two ends of the triple.

[y_prime]

solved in 7:17 - spotted the same X-wing in the video, then used an r4c2/r6c3/r6c4 Y-wing to finish. works out nicely

[angelaraiel]

00:16:18 absolutely lovely puzzle, thanks for this Mark, love these nice ones to reinforce classic sudoku techniques :D

[bobblebardsley]

Solved this one in exactly 20:00, always very happy to complete one in less than the duration of the video (even though I don't have to do an intro etc...)

[briancaster]

Thanks for this puzzle and video, this was the first time I have ever successfully found and used a y wing. I use x wings all the time but every time I'm stuck and look for a y wing I can never find one. But with the title of this video I knew to be on the lookout for one. It took me a while but I found it and finished shortly afterwards. Total time 29:39.

[georgeaman]

That a really nice puzzle. For an easier solution after 13:51 there is an y-wing in r4c2, r4c9 and r5c8. That eliminates 9 from r5c1 and r5c3 and I can reach till the end of puzzle. Thank you Mark for explaining again x and y wings.

[Gofer_]

11:00 flat. Had a blast with that one ! Thanks for all the videos !

[emilywilliams]

This was very interesting, Mark. Especially in that it is a classic, which we don't see very often (especially done slowly - there are a few in the GAS puzzles from time to time), and in that you were able to so clearly demonstrate an x-wing and a y-wing. The latter is very hard for me to spot, but makes sense to me if I can ever see it to start with. I will say that this kind of thing, the sequence of deductions in a y-wing analysis, can look like bifurcation to some (not to me, just to others ... casting my eyes around ...) but it is an essential part of solving a sudoku puzzle. Recognizing a pattern where an elimination can be made that is more than one or two steps away is a vital skill. Thanks for showing us. And thanks, as always, to you and Simon for so faithfully bringing us two videos every single day. I know it takes a lot of dedication - appreciated, truly.

[glennscott]

Hi Mark. Excellent video on searching strategies which is often over looked on Sudoku You Tube. Especially since what you presented is my strategy!

At the end there where every cell is either solved or bivalue except one, you can solve via uniqueness. That forces r6c8 to be a 5 which breaks the puzzle.

[myfyrmadocjones]

18:00 xy wing on r4 c9 using r4c2 and r5c8 mening that r5c1 has to be 7 as it cannot be 9. Alternatively use BUG+1 on r6c8 which has to be 5.

[rhlng]

There are some discussions about the BUG principle. I for one will be more than happy to use it to solve a puzzle. So is the "Unique Rectangle" which of course also assumes the uniqueness of a puzzle. A case in point: at 13:20, one can use UR to remove the 4 from cell (9, 9) and, with Mark's X-Wing on 4, the puzzle pretty much collapses.