Sudoku Secrets No. 2: The X-Wing #shorts

In response to viewer suggestions, we're planning to make a series of YouTube Shorts (videos less than 1minute long) where we explain some of the secrets of sudoku.

This edition looks at The X-Wing. You can find a video where the X-Wing is important here:

[Hari-ldlc]

Love this. Didn't understand a word

[TheFreeBro]

Just a tip Simon. When viewing this on mobile, column nine gets obscured by the like/dislike/comment buttons. Going forward it might be helpful to shrink down the sudoku grid like 5% and move it to the left a little, or avoid using info from column 9. Loving the shorts so far!

[tank]

I've only started doing Sudokus about a year or so, and picking out X-Wings has never been a problem but, I have to be honest, I've never considered the implication that it created a negative constraint that could be exploited...

[mattBLiTZ]

These are impressive speedruns to actually fit a proper explanation within 59 seconds for the limit!

[avantt]

For those who don't understand why the 4 went there:

As he said it can't be on the green cells so if you look to the left, cell four of column one 4 can't go there as there's only a green cell left and you move to the right to see the blank cell has a 4 above it so it can't go there either and so you move again to right and the only blank cell available, which is not green, is the only one that can be a four for that entire row, hope this made sense

[GothMagpie]

Excellent explanation. I’ve been looking for a quick and easy breakdown of the more advanced sudoku rules I’ve read about. This is perfect, thanks so much. ❤

[EelcoWind]

I think the example would be a bit clearer if R4C4 contained a 6, so the influence of the 4 in box 2 only creates the X-wing and is not part of the inference of that X-wing; or some more colour marking showing how certain cells are excluded would also help. Apart from that: all clear!

[elbee]

I must say, these short explanatory videos of high level sudoku strategies are great. Clear, concise and helpful. Just what I need to keep pushing forward in my own puzzle solving. 😀

[Megatron]

Not just the *world's* biggest sudoku channel! The biggest sudoku channel in the multiverse! This channel is "super!"

[annagiousi]

For anyone confused, at 6:20 he used the x-wing technique (r1c2, r4c3, r1c3, r4c2) to locate the 7's . Therefore the remaining 7 is placed on r7c1.

[pianosaresexxy]

You’re doing such a wonderful job with these shorts! Impressively informative and concise. Love the “for how to use this” sign off as well :) Hope these help grow the channel!

[zebfross]

Honestly I’ve never used this technique in a real puzzle, but your “pointing pair” technique I use almost every time.

[jimmahT]

Looking forward to watching your short on the Nori Nori Wing

[christianschmid]

I really looking forward to see which techniques you are going to bring up here.
While I am familiar with the easier ones like X-Wing I struggle to scan for something like swordfish.
I read the explanation, I use it exactly once, and then forget it for half year.

[jptwsdx]

I believe this explanation could be improved.
For starters, it would be useful to gray all the cells where 4 cannot be and then look for row/column where there are only two. This way empty cells (e.g. R3C4) where 4 cannot be, won't be distracting.

I personally prefer an explanation where you bifurcate the two possible cases when placing '4'.

[thefenixfamily]

It feels good to have figured out this method on my own c:

[tracybergamin]

These shorts are fantastic. As a newcomer this helps so much! I would like to see them slightly longer so a real life example could be shown. I do watch the videos but it is all so fast and I get a bit lost :(

[Whatwhat]

"The worlds biggest sudoku channel" is true and amazing

[ramalandajo]

ok but why cant there be a 4 in row 1 column 3 in the beggining and column 8/9 if there is no 4 in row 1?

[LukeSumIpsePatremTe]

For some reason, I think green would be better color to present the possible positions and pink for the places that can't have 4.