This video demonstrates advanced Sudoku solving techniques including hidden pairs (identifying two digits that can only fit in two specific cells within a box), naked triples (three digits that can only fit in three specific cells), claiming (when a digit in a row or column must be placed in a specific box), and bi-value cell analysis (identifying cells that can only contain two possible digits). The walkthrough shows how these techniques work together to systematically eliminate possibilities and place digits in complex puzzles, with the solver demonstrating how to recognize patterns like hidden 6-9 pairs, naked 1-5 pairs, and use corner marks to track digit restrictions across boxes.
Deep Dive
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Deep Dive
NYT Hard Sudoku Walkthrough | May 22, 2026Added:
Hello, let's do the New York Times hard Sudoku for May 22nd, 2026. There's a link in the description if you'd like to try the puzzle yourself and I'm going to get started right now.
All right, starting with this box, 3 4 7 and 8.
Um nothing with three that I can see. The four and then the sevens look in here. Seven looks up, puts a seven in one of these two.
And then the eight.
Not much. All right, let's keep looking at Let's look at the geometry of this box. So we have the nine and the six looking in that aren't yet placed in the box. And so where do they go in this box? There's only two places left, two digits for two cells.
That is what's called a hidden pair. So we can't fit anything else in these two cells other than six and nine. That leaves a triple here, which was always a naked triple. We need a one, two, and five.
Um this one and five look up making this a naked two. And so this is now 1 5.
All right. So follow up down this two.
Two twos look down putting a two in one of these three.
Um the 1 5 pair. So we have three digits left in this row besides 1 5. We need a 3 4 and 8.
I'm seeing the four look up. The three.
Um And so the four ends up in one of these two and that's going to do what's called claiming.
So in this row, we need a four.
It's here or it's here. Wherever the row places the four, it will be in this box also, box three. So we say that row two claims the four from box three removing the four from these cells. These already couldn't have been four. Um but it removes four from here.
Anyway, that means in this box here, where is the four? This four looks in, this four These two fours look up, it that places the four.
Giving us the same result.
Uh Um Anything else here? What about the hidden 6 9? Did that do anything? 1 and 5 were removed from here. This already couldn't have been 1 5.
I don't think that does anything for us right now.
Okay. Um I think that does it for that box.
Um two four These sixes are putting a six in one of these two.
Um nothing else there really. The nine?
Hmm.
Okay. Not seeing anything with nine.
Let's move on to the next box. We have Well, is there any I don't think there's any geometry here.
The eight Actually, the eight looks in this eight looks up. That's a crossing on the 2 6.
That puts an one of these two. That points down. This eight looks up putting an eight in one of these two.
All right.
Um This next box here we've got the two and the seven.
Um >> [snorts] >> I'm not seeing anything.
All right.
Anything else in this band? I don't think so. Let's move on to the next band. 1 2 and 9. The two ones look in.
This one looks up placing this one. Now these two ones look up. The 1 5 pair said not one there. So the one's in one of these two.
Um okay, that was the one. The two I don't think there's anything else with two. Is there? Oh, there's a crossing actually. This two looks in. This two looks down putting a two in one in one of these two.
That points in here with this two. This two looks down, putting a two on one of these two.
And then the nine.
Nothing from nine. All right, how about this one four here?
So, we already took care of the fours, the one.
Hm.
Something I'm noticing is that this cell's not one. It's also not the seven or the eight. So, in these four cells we need to place one, seven, and eight.
That's three out of the four digits.
That means that this is at most two candidates, a bi-value cell.
So, it's not one, two. It could be three. It's not four. It could be five.
And that should be it. It's not six, seven, eight, or nine.
So, it is down to three, five only, as predicted. In fact, this whole column's just four digits. It's two, three, five, six.
So, this is two, three, six. This is three, five, six. This can't be three or six, so this is two, five.
All right. Some good markings there.
Nothing else with this box, I think. And then we've got one, five, and six here.
So.
Ah. These fives look into this box, placing this five.
Two fives look up. This isn't five cuz we have our handy one five pair there.
Doing lots of work. That places the five in this box, which then resolves this bi-value that we just found. Makes it three. That makes that an eight.
That's four, and that's three.
All right. Um let's clean this up a little bit. Oops, I cleaned up the wrong digit.
Um Three digits left in this box. We need a one, five, seven. This can't be the five, so this is or seven. So, this is a naked one, placing this one.
This is a five seven pair, leaving this as only six nine. Nice. And then this whole box just needs a six eight nine.
We know the eight's up here.
All right.
Um that's quite nice. We just got some digits. We should follow up on them.
The 1 3 4 and 8 maybe.
So, these ones look down. This one looks in putting a one in one of these two.
What about this three I just got?
I don't really see it doing anything.
The eight. We have the eights already.
Okay, what about this box? We got 1 3 4 5 maybe.
The ones are done. The fives are done.
The threes do look in here putting a three in one of these two.
Okay, and then the fours look in here. This four looks in placing the four in this box which then places the two. Notice there was a two corner mark in here. There's no longer a two corner mark telling us that two has been further restricted in this box down to just one cell. So, that's a hidden single. We can place it. And now that had a three corner mark in it, it's now a two. So, the three can only go here. So, we can just cascade those corner marks. That's what makes them very useful.
Um, one of the one of many reasons they're useful actually. Um, but it is a good reason.
The all these fours look in placing this four. These two fours look down. These two fours look in placing that four.
That did use up a two corner mark, but there's still two places for two. So, we can't place it yet.
Um, we do maybe want to see Yeah, I mean, um, we could see where two goes in this row. Unfortunately, there are still two places and they don't share a box. So, what's this down to? This isn't eight.
So, the eight in this column goes here.
And it's down to 6 9.
Nice.
Um, these three digits.
We need a 7 8 9.
That's not nine.
This is 7 9 only. It's not an eight.
So, in this column where does eight go?
It goes in one of these two. That removes eight from this cell here.
Um, four did Oh, no, it's five digits in the column.
Yeah.
It's tempting to say that this is the same as this and this is the same as this, but that is not actually how it has to resolve.
Uh anyway, um actually, is it how it has to resolve?
If this is nine, that could be nine and then No, yeah, maybe that is how it resolves.
Trying to think.
Anyway, it doesn't matter. We'll see if they that ends up being true.
Um can't do anything with it.
This row is down to four digits. We need a 5 7 8 9.
This can't be 7 8 or 9, so this is our five, giving us one and five.
So, these are our 7 8 9. This one can't be nine, so that's 7 8.
This is 7 9 cuz it can't be 8. So, this is the only place for 8 in the row.
These two eights look down, eight looks in, putting an eight one of these two.
Um sorry, I keep I keep coming back to this. We can we can kind of prove that the this is the same as this and this is the same as this.
So, if this were a six, where does six go in the column? It would go here.
And that forces this to be the same digit as this, whether it's seven or nine, it's going to get placed there.
Uh the only other option is this is nine. If it's nine, we don't know where it goes in this column. Could be either of these, but it does make this one a seven. And now seven in this column would go here, making these two the same and now the nine ends up up here. So, this these digits are the same and these digits are the same as each other. I don't think it actually does anything, but that I thought I'd uh point out that I did eventually think of a proof there. All right, we need two, three, and se- uh six, two, three, six.
This can't be two, so three, six.
This can't be three or six, so this is a naked two.
That makes that five, six, and two.
Um that's a 3, that's a 6.
Um Let's see.
Two digits left in this box. We need a 6 7.
The 6 looks in, so that's 7, that's 6. I think we're wrapping up. This is 9 and 6, that's 6 and 9.
That's a 7 8 and 9. We get the 9 here, that's 8, that's 9, that's 7. These two are the same, these two are the same.
That was one of the cases I talked about.
Um, this row we need a 5. That's 7 and 5. Here I need a 3 and a 7. So, that's 3, that's 7.
Over here I need a 2 6 8.
The 6 can only go here. We have these two 6s. Then we have a 2 8 pair. The 2 looks down though. That's 8, that's 2.
Sorry, 2 looks across.
That's an 8 there. Um, these two digits for the column are We do need a 1 and No, it's 1 and 9. Okay, this 9 looks in, that's 1, that's 9. That places this 1.
Uh, these two digits we do need a 3 which goes 3, which goes there.
Um, and this is a 7.
This row needs a 9. And then we're down to 2 and 3, that's 2, that's 3. And we're done.
All right, not too bad today.
Um, some good crossings in this one.
Uh, some good hidden pairs.
Not really much else to speak of.
Just uh, needed to scan well.
All right. Well, how'd you do?
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