Can you close out this puzzle? | Ziplock by James Sinclair

Added: 2026-05-05

[00:00:10]Hello, good day and welcome. I'm Touab and today I'm going to solve Ziplo by James Sinclair.

[00:00:17]This is a puzzle from um Artisal Sudoku volume 225.

[00:00:25]um that number is a multiple of 45.

[00:00:31]And what James does is uh he gives the puzzles that would normally be in the paid subscription level. He makes them available to people who are free subscribers. So, um this gives you an opportunity to see what kind of puzzles um you might be able to uh experience if you are a paid subscriber. Plus, you get the um hints as to how to solve all of the puzzles in the um uh in the uh newsletter.

[00:01:09]So, um because this is actually publicly available, I am going to solve it for you. hopefully. Um, and we shall see.

[00:01:19]This is uh meant to be uh it's 9 out of 10 on uh James' scale, which probably equates to maybe a 2.5 to a three on the Logic Masters Germany scale. So, um little trickier of the ones that James tends to put out. um but should still be uh reasonably well within reach for people who are somewhat experienced at Sudoku.

[00:01:47]All right, if you'd like to try this puzzle for yourself, it will of course be the first link in the description and there will also be links to uh Artisal Sudoku as well.

[00:01:58]Let's have a look at the rules. Normal Sudoku rules apply. So, we're going to place the digits one to nine once each in every row, every column, and every box.

[00:02:10]Zipper lines along lavender lines. Each pair of digits that are the same distance from the center of the line have a sum equal to the digit in the center cell. What does that mean? That means that those two uh those two red digits are going to sum to that blue digit. And these two yellow digits are also going to sum to that blue digit. And these two pink digits are also going to sum to that blue digit. And so on. And the same applies to all of these lines.

[00:02:45]Okay. Um digits in cells separated by a black dot have a 1:2 ratio. So if this were a two, this would have to be a one.

[00:02:54]So that two is double one or a four because four is double two.

[00:03:00]Okay.

[00:03:01]Uh that is all the rules. So I am going to restart the puzzle to reset the timer and let's begin.

[00:03:08]All right. The first thing to consider is that um uh if n is on a zipper line, it can only go in uh a um in the central cell because if it if I had a nine here for example, what could I make that so that this digit plus this digit uh was equal to that? It would have to be 10 or more.

[00:03:37]So that must be a nine cuz it's the only um well all the cells are on a zipper.

[00:03:43]So the in this box so the central cell has to be the nine.

[00:03:48]Um now that prevents this from being a nine.

[00:03:54]Um but something else to note is that a um the the sum cell the central cell cannot go on the zipper line itself because if it did it would be um we would need a zero on the other appropriate location. So, um, that digit, which I'm going to mark yellow, can't go there by sudoku. Can't go on the zipper by, um, zip line logic. And so, that must go there.

[00:04:33]And we can do the same down here, I think. Yes, we can.

[00:04:39]Uh, let's mark that one red. And that one red.

[00:04:46]Okay, now we can see that because this can't be nine and therefore this can't be nine.

[00:04:56]Nine can't go on a zipper line. So, one of those is nine and one of those is nine.

[00:05:03]That means that those are not nine.

[00:05:08]Uh, and those are not nine. And in fact, we know that those are not nine because they can't go. You can't put a nine on zipper unless it's in the middle. So, one of those two is nine. That means one of those two is nine.

[00:05:27]Okay.

[00:05:35]So, I have to be able to sum to this value in at least three different ways.

[00:05:44]because I've got one pair of digits there. I've got have to have a different pair of digits here.

[00:05:51]And because those two see each other, they have to be different digits.

[00:05:59]Um, but I can't have a repeat because this still has to be a fifth digit. uh I have to have five different digits here. So um I can't have um five or six because there are only two different ways with two digits. I can't do the six because these two can't both be three.

[00:06:28]Uh so this is at least a seven and we know it's not nine. So that's a seven or an eight. And we I think we have the same logic here that I need at least three different ways to sum to this value. I can't use the six with the repeated three because there's nowhere for a repeated three to go. So, this is also seven or eight. Now, could they be the same?

[00:06:53]And I don't see an obvious reason why not yet.

[00:07:02]Okay, but let's consider that.

[00:07:05]That puts yellow into um one of those three and it puts red into one of those three. If they are the same, then they go onto this cell, which means they couldn't be eight cuz this can't be nine.

[00:07:30]Could they be seven?

[00:07:37]If they were both seven, then that would be one. That would be eight.

[00:07:46]That would be seven.

[00:07:49]But where would eight go in this box?

[00:07:57]Okay. Yeah. So, if another way to look at it, if this is seven, then eight can't go on the zipper line. and then eight is in one of those.

[00:08:08]If this is eight, then eight is here.

[00:08:12]Therefore, this cell can't be an eight.

[00:08:16]Um, so now it's at most a seven.

[00:08:21]And now, uh, neither red nor yellow can go on this zipper line.

[00:08:32]So, this one has to be red.

[00:08:35]Yeah, it can't go on the zipper line.

[00:08:38]That has to be red.

[00:08:40]Uh, this one has to be yellow.

[00:08:44]But we know that these two are different. This is seven or eight. These two are different. So, so now we know that um, uh, yellow and red are different. Uh, we can place a nine there because the yellow seven or had to go here.

[00:09:04]This has to have at least two ways to fill it.

[00:09:08]Um, uh, sorry, at least two ways to sum to have two digits sum to it. Um, so it can't be three or four. So that has to be five or six.

[00:09:21]If this is a five, then this is a six.

[00:09:23]If this is a six, then this is a three because we would have 2 4 and 1 5 on here.

[00:09:38]Where does red go in this box?

[00:09:43]And it has to go. It can't go in any of those. It does go on one of those. I don't know exactly where, but therefore it is less than yellow. So, yellow is eight, red is seven.

[00:10:00]Um, because I can't put a repeated digit.

[00:10:04]Sorry, let me rephrase that. Because I can't um put uh half of eight. I can't put four um with another four. Four must be in one of those.

[00:10:21]Um, eight must be one of those. I can't put eight on the line.

[00:10:27]That means that eight is in one of those three.

[00:10:34]Okay.

[00:10:38]So, what's going on here? It can't be seven or eight.

[00:10:46]Um, it can't be five because if it were five, then all of those digits would have to be from 1 2 3 and four. And that's too many cells for 1 2 3 and four to go in.

[00:11:04]I'd have a repeated digit.

[00:11:08]So, that's either six or nine.

[00:11:26]Okay, that's nice.

[00:11:30]If this is six, then where does eight go in this box?

[00:11:38]Um, in fact, where does eight go in this row?

[00:11:44]If this is six, eight can't go on the line and so it must go here. But if this is six, where does seven go in column 8?

[00:11:55]It can't go on the line at all. So it must go here. So that would be simultaneously seven and eight. And that's not going to work. That cannot be six. This must be nine.

[00:12:12]Okay, those black dots are offset from each other. I perhaps hadn't appreciated that before.

[00:12:24]Um, right. So, I don't think this can be a 36 pair.

[00:12:37]I don't think these dots can be 3 six because if that were 3 six then by zip line that would be 3 six cuz the three would go with a six and the six would go with a three.

[00:12:52]Um so if those two are three and six then those two are three and six but if this is three and six then this is also three and six and we'd have a repeated digit.

[00:13:02]So these must be from 1 2 4 and 8.

[00:13:10]Okay, these this one and this one are both on black dot. So if that were two, that would have to be seven.

[00:13:19]Uh so neither of those can be two. If one of them is four, the other would have to be five.

[00:13:26]So they can't be four. That's one or eight. And that makes these two and two or four. One would go with two. Eight will go with four. And now two and four makes this five or seven.

[00:13:42]And similarly that's going to be five or 7.

[00:14:04]Okay, if this is two, that's one making that eight, making that four, making that five. So that's 215.

[00:14:16]And then this would be 7 8 4.

[00:14:23]But if this is 48, then that's one and that's two and that's seven. 487 and 215.

[00:14:32]So this cell sees 1 2 4 5 7 8 and 9. It sees all of those digits. So that is three or six. And because three and six together sum to nine, that means I can't put three or six in those. I can't make that a 3 six pair because that would break.

[00:15:20]Okay.

[00:15:25]Um, if that's an eight, then that's a one.

[00:15:37]which makes that eight and that one.

[00:15:54]Oh, that eight is looking across. That's a one.

[00:15:58]Um making that two which means that that is seven that is 8 that is four that is five.

[00:16:25]So what's that digit?

[00:16:28]That se is 1, two.

[00:16:31]It can't be three because that would force that to be six which would break that.

[00:16:36]It can't be four. It can't be five.

[00:16:40]It can't be six for the same reason. It can't be eight. It can't be nine. That's a seven.

[00:16:45]Which makes that a two.

[00:16:54]That puts a seven into one of those.

[00:17:01]Oh, that's not an eight. That makes that an eight nine pair.

[00:17:08]That one's not nine.

[00:17:15]Eight is in one of those two.

[00:17:27]Okay, we know that's not three or six.

[00:17:31]So, it sees uh it could be can't be one, two, can't be three, could be four, can't be five, can't be six, can't be seven.

[00:17:51]Can't be nine. So that's that could be four. Was that?

[00:18:00]Yeah. So that is either four or eight.

[00:18:03]Let's just double check that. Can't be one. Can't be two. Can't be three because that would be six.

[00:18:12]Um could be four.

[00:18:16]Can't be five. Can't be six for the same reason. It can't be three. Uh, can't be seven. Could be eight. Can't be nine.

[00:18:23]So, that's four or eight. That makes this one or five.

[00:18:41]Okay.

[00:18:44]Um, that puts two into one of those two.

[00:18:58]Ah, it puts seven into one of those.

[00:19:01]Sorry, one of those three for two.

[00:19:04]Uh, seven though is definitely one of those two.

[00:19:08]So, that has to be a one seven pair.

[00:19:12]That makes that a one.

[00:19:18]That means that one of these two is one.

[00:19:22]If that's one, then that would be six. I don't see a obvious problem with that right now.

[00:19:34]Oh, if that's a one seven pair, where does one go in row uh two? That has to go there. And that makes this an eight. So that is not eight.

[00:19:59]So where does nine go in this column?

[00:20:03]That has to go here.

[00:20:06]Where does nine go in this row? That has to go here.

[00:20:25]Okay.

[00:20:35]So, this digit has to go there.

[00:20:49]Which means it has to be 4 2 3 or six.

[00:21:14]Right? That can't be a four because if that were a four then this would have to be four which it can't be. So that can't be a four. So that mean but that that digit must go there. So that is a four.

[00:21:27]This is now 2, three or six.

[00:21:35]Is that right? Yes. Cuz wait yes this digit has to be one of those three and it can't be four.

[00:21:52]So that's 2, three or six.

[00:21:56]So if that is two that would make this six.

[00:22:03]If that's three that's five.

[00:22:06]If that's six, that's two. So that's two, six, or five.

[00:22:14]But where does five go in this row? Five goes on one of these two.

[00:22:19]Okay, that makes that a three, five pair. That makes that six.

[00:22:25]Um, those can't be three or five.

[00:22:38]Right. That that can't be five because if that were five. Yeah. Because of the uh just by Sudoku. And if that can't be five, that can't be two.

[00:22:55]And the three here would require that to be five. So that's a six. That's a two.

[00:23:02]Wait, I'm messing up. That's not a five.

[00:23:06]That's a not a three. That's a two six pair.

[00:23:14]My brain was not adding up to eight properly.

[00:23:17]Okay, that's a two six pair.

[00:23:21]That can't be three. It's not a four.

[00:23:23]That's two or six.

[00:23:27]But um yes, if this is five, this has to be six. And if that's not five, then it's six. So that can't be six. That's a two.

[00:23:41]That's a six. That's a two. These two digits are three and five.

[00:23:48]These three digits are 469.

[00:23:58]And that one is not a nine.

[00:24:02]Okay. And then these two digits are three and eight.

[00:24:15]Okay.

[00:24:19]That worked.

[00:24:24]Right. This digit has to go here because um again this digit can't go on this line or um it would have another partner of the same value elsewhere on the line.

[00:24:51]Um, so has to go there because we know it's not nine and it can't go there by Sudoku.

[00:25:01]So, uh, that can't be two or eight.

[00:25:09]Uh, yeah, that can't be a two or eight that cell.

[00:25:15]So, that has to be the eight.

[00:25:18]That makes that a one, which now makes that six. And that six. And that makes that three. And that makes that six.

[00:25:30]And this can't be. Neither of those can be one. So that is a 1 five pair. This is a two four pair.

[00:25:40]Okay.

[00:25:43]One of these is a two, which means the other one is a five.

[00:25:50]Uh, and this is a three four pair and that matches for the column as well.

[00:25:55]Good.

[00:25:58]This eight is looking up. That's three.

[00:26:00]That's eight. So these two digits are four and five.

[00:26:07]And then these are 379.

[00:26:13]And this one is not nine. And let's remove the quarter marks.

[00:26:22]Okay, these two digits are two and four. And we know the order.

[00:26:30]That's four. That is two.

[00:26:33]If that were nine, this would have to be seven.

[00:26:38]Uh, which it cannot be. In fact, um, that's the only place that six can go in the row. That's an eight. That's a nine.

[00:26:47]I've got my two four pair over here making that five. Uh that five and that three. This is four and two.

[00:26:57]And then these three digits are 135.

[00:27:04]And that's not a one.

[00:27:07]Okay. This is where nine goes in column five.

[00:27:25]one in this column.

[00:27:29]Uh and five in this column.

[00:27:34]Uh yes, that must be a one five pair.

[00:28:00]H. Um. Oh, this four is looking up. So that's six and that is four.

[00:28:15]Two in this column can only go there.

[00:28:17]And that makes that seven.

[00:28:21]Uh that resolves this to a three making that a seven nine pair there.

[00:28:31]This cell is 1 3 or five um by the column. If that's a one then that would be eight which it can't be.

[00:28:41]So that's not a one. I now have a three five pair. That's a one.

[00:28:46]So if this is three then this is six and if this is five this is four.

[00:28:54]So that's four or six.

[00:29:04]Eight can't be in either of those two or that one. So that's an eight. Making that a one. That resolves my five and my one here.

[00:29:29]Okay.

[00:29:36]Where does nine go in this row?

[00:29:41]Um, by sudoku it can go here or here.

[00:29:46]But if this were a nine, this would be an eight, which it can't be. So that's nine. That's seven.

[00:29:54]That puts a nine here.

[00:29:57]Let's type that correctly.

[00:30:01]That can't be seven or that would be six.

[00:30:04]It can't be six. It can't be five.

[00:30:10]Uh, if that were four, that would be three, which it can't be. So, that must be three and two.

[00:30:20]Um, that gives me four, five or six to complete the row, but it can't be a five. So, that's four or six. That gives me a four, six pair. That makes that five and that four.

[00:30:38]Um I have a three five pair in this column making this four or six and this three or five but that four is looking there. So that's a six which makes that four that's five that's three. We get five and three resolved which resolves this five and three.

[00:31:00]Uh this is a six.

[00:31:03]These two digits are seven and four. It looks like uh so that's four. That's seven. That makes this one and this seven.

[00:31:20]Um this one makes this five and this one. This four makes this two and this four. And this five makes this three and this five.

[00:31:35]Um that was a really delightful puzzle.

[00:31:38]um uh very much a um it feels very much like a James Sinclair puzzle because he's cleverly um using uh all kinds of different geometry to push digits in certain places and um being able to make use of some of the symmetries. um like figuring out that what is going on this line here is the same as what's going on this line and then this beautifully showing that the seven and eight had to be different and indeed then which one had to be which I really really enjoyed this puzzle. The other bit I really liked was the 3 six getting 3 six off of here. Um, but yeah, that's uh a really really nice puzzle. Well, if you enjoyed this solve, then please hit the like button. You can subscribe to see some more and I would love to hear your comments. I'm looking forward to next time be seeing you.