Sudoku Adventure #1164 - "Four Square" by Strosahl

Añadido: 2026-05-06

[00:00:00]Hello, let's continue our Sudoku adventure with four square by Strassol.

[00:00:04]So, we have normal 6 by 6 Sudoku rules.

[00:00:06]That means in each row, each column, and each 2 by 3 box, we are placing the digits 1 to 6 exactly once each. We also have killer cages. Those are these cells surrounded by dotted lines. The dotted lines are the cage.

[00:00:17]Digits in a cage sum to the value in the top left. So, these four would sum to 12.

[00:00:22]These four sum to 15.

[00:00:24]Uh in addition to that, we do have these circles with digits in them. These are quadruples.

[00:00:29]Um they always touch four cells, and the the numbers in them describe numbers that must appear at least once in those four cells. So, somewhere in these four cells, we need a four and we need a six. We could have multiple fours. We could have multiple sixes. Like we could do this if we wanted.

[00:00:45]Or, you know, we could only include one of each somewhere. But, the point is we need a four and a six. We can't omit the six. So, this wouldn't be allowed.

[00:00:54]And that's it. Those are the rules.

[00:00:56]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.

[00:01:02]Okay. We have a lot of Audis here. Uh let's start with the 15.

[00:01:08]So, what do I mean by Audis? Well, we know that these four digits sum to 15.

[00:01:12]We also know that these six digits sum to 21.

[00:01:16]Because 1 to 6 sums to 21, and that that's a box that has 1 to 6. So, we can subtract uh 21 minus 15 to get what these two have to add to.

[00:01:25]So, 21 minus 15 is six. So, these two add to six. So, they're either 1 5 or 2 4.

[00:01:31]Um these two add to nine. So, they're either 4 5 or 3 6.

[00:01:37]So, that's the same here.

[00:01:39]Now, this can't be 4 5.

[00:01:41]If this was a 4 5 pair, we would not be able to add to six here. Right? We'd have had up only 1 and 2 left. So, this has to be 3 6.

[00:01:50]And in fact, that makes this 1 2 4 5 as well.

[00:01:54]Um the Audis here, uh 21 minus 13 is eight.

[00:01:59]So, we're either 2 6 or 3 5.

[00:02:03]Now, we have a problem with 3 5 for similar reasons. If we remove 3 and 5, this adds to 10, which isn't what we're supposed to add to. We're supposed to add to nine.

[00:02:11]So, this has to be 2 6. And then that makes this not 3 6. It has to be 4 5.

[00:02:18]Okay. The Audis here, 21 minus 14 is seven. Unfortunately, seven ha- doesn't eliminate any digits naturally.

[00:02:27]1 6 2 5 or 3 4.

[00:02:29]This is 12 again. So, that's going to be nine. Uh 4 5 or 3 6. So, this can't be 4 5 because it makes this 1 2.

[00:02:42]And then now this is also 4 5, but we're not supposed to add to nine. We're supposed to add to six.

[00:02:47]So, this has to be the 3 6.

[00:02:50]Um So, this is also 1 2 4 5.

[00:02:56]And 1 plus 2 plus 4 plus 5 is 12. So, we're doing the math right.

[00:03:02]Okay. Um I could fill what these are.

[00:03:05]Okay, we do have quads. I wonder if the quads are helpful at this point. So, because of this 4 5 pair, we know neither of these are four. So, that means we need a four in this quad still, but it's got to be down here. So, four is in one of these two.

[00:03:15]That's going to point saying these aren't four, and that puts a four in one of these two.

[00:03:20]Um we are going to need a two here.

[00:03:22]So, the two can't go in one of these two. So, the two ends up in one of these two. That again points telling us those aren't two, and two is one of those.

[00:03:30]Uh 3 6 doesn't go here or here. So, this is 3 6.

[00:03:34]That adds to nine. Um in fact, so that means that these add to six. So, we I guess it it's just Sudoku. The these are the other way to add to six, the 1 2 4 5 way. And so, that means this adds to six.

[00:03:50]Because if this adds if we're adding to six in one way here, we're adding to six in the other way here.

[00:03:58]So, if this adds to six, this also adds to six.

[00:04:04]And that means this adds to six. This adds Yeah, so these all add to six.

[00:04:07]These are a bunch of vertical six cages here that I need to resolve somehow.

[00:04:11]Okay, that makes sense if you think about it a little harder. Um We need a three in this quad, and these can't be three. So, this is our three, and this is our six.

[00:04:22]Okay.

[00:04:23]Um The 14 added to seven.

[00:04:28]Could be 2 5. It could be 4 Okay, so this can't be a four. Because if this was four, this would have to be three to add to seven for the Audi, but this can't be three.

[00:04:37]So, this can't be the four. Placing the four here. So, these add to 10 and three, which we know what this pair is though.

[00:04:43]This is a 1 3 pair. That's one, that's three.

[00:04:46]And so, all together, these add to eight. We need to get to 14. So, this can't be the two, first of all.

[00:04:54]Um what is it? Six?

[00:04:56]And that's five.

[00:04:58]So, this is the 1 2 pair. This is the 4 5 pair.

[00:05:02]Okay.

[00:05:04]Doing well. Um I still need a six in this quad. It's in one of these two.

[00:05:08]Actually, it's placed.

[00:05:11]And that gives us the three and six here.

[00:05:14]I have the two. I have four and six. I do not have my five. Then it goes there.

[00:05:18]Remember, these add to six. So, that's five and one. This is two and four. This is five and one.

[00:05:23]This is two and four.

[00:05:25]So, that means this is 1 5. This is 2 4.

[00:05:27]I'm pretty sure we're vertically roped.

[00:05:28]I probably could have noted that, but we didn't need to use it.

[00:05:31]That's four and five. That's two and four.

[00:05:35]Um this digit is the one. These two digits are the two and three. Three two like that.

[00:05:41]And down here, uh oh, I didn't get my five yet on this quad. So, that's 5 1.

[00:05:51]So, I guess I could just get these pairs. We need a 3 5 here. Okay, so that's three, that's five.

[00:05:57]We have six and three, two and six, four and two. And then I need the one and the four, and we're done.

[00:06:02]All right, nice puzzle Strassol. I enjoyed that. Um I liked uh I probably could have used the vertical roping here to to speed things along a little bit, but I basically discovered the same thing that you know, we had the the 3 6 columns, and then we had the columns that add to six.

[00:06:19]Um that was neat.

[00:06:21]A nice use of Audis there.

[00:06:23]Uh let me know how you did, and if you enjoyed this, why don't leave a like, subscribe, and a kind comment below.