But The Top 5 Rows Are Empty?!

[Music] [Applause] [Music] hello and welcome to thursday's edition of cracking the cryptic and a visually arresting puzzle today uh from richard stoke the sudoku professor um unusually this puzzle is not from his sudoku variant series which we featured on the channel a few times before but this is a puzzle he made for possible inclusion in the world sudoku championship back in sophia in 2015 and as always in these competition environments there are puzzles that don't get used in the championship for one reason or another often on grounds of difficulty and then those puzzles might be used in other championships or competitions online but this one richard viewed as simply too special uh not to share it with the public so he published it on logic masters germany about five years ago um in order to uh get as wide of audience as possible for the puzzle i mean a puzzle that appears in the world sudoku championship especially the latter stages of the world stoker championship might only be solved by sort of five people or even less than that so you can well understand why richard would want a puzzle that looks i mean it's ridiculous i mean how can you have a puzzle that only has these digits now there is one extra rule here which is a non-consecutive constraint but even so it seems a bit unlikely that this puzzle that you can work out what goes in these top three boxes but we shall give it a go we shall give it a go now richard is one of the authors who is going to be appearing in our kickstarter book um so if you do solve this puzzle and you love it do let us know so we can think about including it in the book i did a quick check-in just now on the campaign which only launched two or three days ago and we are already very very close to reaching the stretch goal which will allow us to put new puzzles from some of the world's best constructors into the book now this is incredibly exciting especially for me um because uh you know this these these innovative puzzles that they create are the reasons for this channel um it's because i love solving them so much so the thought that we might get a whole slew of extra puzzles from um from these great names is genuinely fantastic um so please do support it if you haven't already um and if we it's possible we'll actually meet that goal by the time this video goes live tonight and if we have the next goal is also pretty exciting um it will mean that we include in the book a harry potter style sudoku hunt um so our harry potter hunt was so popular a couple of months back and we will be able to make a brand new hunt and put that into the book as well which i know for some of you will be a big um well something you'd look forward to now so yeah i'll put a card on the screen where do i put the card i have to put it here there just there um and of course there'll be a link under the video as well now what are the rules for this one well they are very simple we have normal sudoku rules apply and we have horizontally and vertically adjacent cells cannot contain consecutive digits that's it so what does that mean so that means let's imagine this square's a 5 that would mean none of those squares could be a 4 or a 6 because they are orthogonally connected with the five and obviously four is the is consecutive with five and so is six so that's how the constraint works and that's all we get in order to build up this puzzle up to the top so do have a go the way to play as usual is to click the link under the video and with that let's get cracking um and i have not i mean there's not really much we can do here is there i'm gonna have to i'm going to have a look at this row in the absence of many better ideas this has got to be one two three and nine into the open cells so we can see we can't put nine here three here because of the four um now that one is completely unrestricted and that one that one can't have two or three in it look because two two is consecutive with the three and the three is in the box right that's not exactly what i was hoping for i've got to be honest um all right let's have a look at this row instead we've got two five seven and eight well that one can't be two or eight because it would be consecutive with nine so that's got to be five or seven ah okay now now look at this row i've just noticed something where does five go in this row it can't ever go next to a four so those cells are ruled out and it can't go next to a six so five is a sort of hidden single in this row it can only go in that position uh does that matter not sure let's carry on we need two seven and eight now into the open cells now can we get any more eliminations yes we can eliminate eight from there seven ah seven and yeah seven and two from this square because of the non-consecutive you can't put a two next to a three you can't put a seven next to a six so this is eight um you can't the one rules this out from being a two so this is a seven this is a two ah ah look at this look at the seven and well more importantly i think this six is sort of all powerful regarding box eight because it rules out all all four of those squares from being a seven well this seven rules out that one there's only one place for a seven it's got to go here seven can't go next to a six in box nine look so it can't go there it must go here good grief okay so we could actually make a start and now now we've got five digits in this row so let's have a look at this one now we need one two six and eight so that one oops that one can't be one sorry it can't be two or or eight but it could be one or six it can't be two because it would be next to a three so one two six and eight one two and six here because of the eight in the box and the nine above it one two and eight here one two and eight here ah that one can't be two because of the three it's so easy to miss these constraints um oh that one can't be six because there's a seven next to it [Music] right okay in fact now look at this row where does 6 go in it it can only go in this square the 7 rules the 6 out from that one the 6 rules the 6 out from that one and that six rules it out from that one so this is a six six must ah six must live at the bottom of box nine and can't be next to a five and can't be in the same column as itself so six goes there so this box now maybe we need to put a two into it one two eight nine that's really not very helpful um [Music] that one can't be one i can see that i can't see much much more i have to say good grief okay so what do we do now we've got uh ah where does five go in this box look five can't go in those two so it must go in one of those doesn't actually help us very much but it's something oh no yes it does help us because look fours must also be in one of those three positions now you can't put four in the middle of those because if you do the five will definitely be connected on one side or the other so in fact this is a four or five pair in box seven this must be ah this is the same point again look this has got to be a one two or a three well it can't be a three because then it will definitely be next to a four so it's not a three that means the only place for a three in this box now is here so that's not a three the three can't be next to a two so it sorts that all out as well so now all of a sudden we have a flurry of activity that can't be a one can we go any further with this we've got quite a lot of this row done now look we need yeah we've got five digits we need two three eight and nine so two three eight nine into those squares that can't be eight because it would be next to a seven uh that one can't be two because there's a two above it good grief how do i not spot that look that's a two it does tidy up a few pencil marks all of a sudden this two can't be next to a three so where does three go in this row now i don't believe it it's got to go there and the problem is there's so many opportunities to miss one of these little connections and it totally will break you in terms of efficiency for the puzzle um [Music] look i mean look and although we've done really well at the bottom how on earth do we get into the top of the grid i guess what we can say is that there simply cannot be much to do up here because the non-consecutive constraint is going to be so feeble when it comes to this these top three boxes at least with these two rows well especially this row at least in this row the non-consecutive constraint is immediately applying so i think we have to focus attention here now can we see anything clever oh my my door someone's at the door one second right sorry about that it was a dhl man maskless um and uh right what we were looking at we were looking at this row and we were trying to spot whether any of the digits were restricted five isn't bad is it because five can't go in those three and it can't go next to four and it can't be in the same column as those and it can't go here because it would be next to a six so five is in one of those two positions which that's almost good but not quite good enough um six is maybe six can't go there and it can't go above a seven can't go here because of the six can't go above a five yeah six is nice isn't it can't go there so six is in one of those two and that does it that does it because now now this can't be a five because if we put five in here where do we put the six in the row we have to put it there and these two are most certainly consecutive so we get the five over there so that's not five anymore is that all we get from that ah ah no it's not it's not because it's this five rules the roost over box six regarding four four can't go there either because of the column so four goes here beautiful look this look at how that impacts on this box now where do we put the four in it we can't put it next to a three or a five so it takes the position of a six which means that must be the six and where does five go now in this box this five rules out those two you can't put one next to a six you can't put one next to a four so that's a five i'm still working on this i've just noticed 8 is very restricted as well where does eight go in this row can't go there can't go next to a seven and can't go here so it's in one of those two positions now is that is that useful um i don't know is the answer seven in this box can't go in either of those two squares so seven must be in one of those two positions when i get these pairs by the way in non-consecutive i immediately am thinking how does this impact six and eight because in this case it's useless because there's already a six and an eight in the box but once you get a seven and a pair in a box like this you know that you can't put a six or an eight in either of these two cells so seven seven's got to be in one of those cells ah well okay yeah this is good enough because now we can do exactly that we're regarding eight this can't be an eight because if we make that an eight this has to be a seven which it can't be because that's now consecutive so once we lock the seven into this domino we can get rid of the eight as a possibility so this becomes an eight so so ah right six eight pairs now on box four ruled out from all of those squares so this is a 6 8 pair which means this can't be a 7 because if it was a 7 it would be next to a 6 or an a it's just ridiculous setting it's ridiculous these two squares are one and two and the one down here fixes the order one two there's a two seven pair over on this side of the grid so those must be three and nine and you can see that with this 4 here we can actually determine the order this 9 rules and 9 out from that cell this 8 rule yes do a bit of scanning we can actually get a bit done in the bottom of the grid look two eight nine one eight four five this mustn't neglect sudoku um that's gotta be a one to complete this row these two squares have got to be three and nine and we can do that as well just by sudoku using the 9 here and we can use the 3 to determine which of these is correct so this can't be a 2 so that's 7 and 2 and all of a sudden we are now into the top of the grid so let's have a look we need one two and five in there and that's immediately well partially resolvable you can't put the one or the two in the middle of the column because it will then be next to the two so this is a classic non-consecutive trick so the only way of this working is if we use the five to keep the one and the two apart so let's check these ones now we need four seven and nine four seven nine that one can't be four because it would be next to a five um i don't know can't see anything else there so this must be three six and eight and that one can't be three because it would be next to a four but i'm not actually seeing anything better than that so let's look at this one we need three four and six again again three and four are consecutive with each other so you can't put them in the middle of the three so the middle of the three must be the six playing gooseberry on the three and the four some people asked what that phrase meant playing gooseberry it says obviously a britishism um it means sort of an unwanted companion to make three when two people want to be alone with each other um okay this two seven and nine into those cells that can't be seven because of the six i'm still not figuring out how to do this though i'm getting you know an occasional digit but it's not falling over one five and eight into these so that can't be five i keep expecting like this three to impact this one and it keeps not doing it let's have a look at this column then and hope uh two five and nine again the five is having a little impact but and the other one does impact this cell two nine pair in row two thank goodness for that so this is a seven that fixes that this can't be eight look so that's a three so in this row now look we've got effectively six digits that we've locked in we just need one four and eight this square can't be a four so that's also one or eight so the only place four can go in the row is there now that also though is not very helpful okay let's have a look at this column we've got six digits again so we need six seven and eight this one can't be seven because it would be next to a six or an eight that's clever isn't it again so the seven goes up there unfortunately the seven doesn't impact this square no it's still it's still resisting one three six and eight into those squares so one three six eight now we can remove six and eight from this square because of the seven so this becomes a one or a three we can no oh we've got a six eight pair there so we can remove six and eight from there as well so now we get a one three pair in this column which makes this one have to be an eight that have to be a one and maybe that yeah this is nice so the one fixes that this now can't be a two nine seven the two fixes the two and the one over here that fixes a two here this eight fixes the six the eight the six the six and the eight get resolved now we can't put eight next to nine so the four and the nine get figured out the nine and the five get figured out the five and the eight get figured out and there must be a one yeah one three three and four check that's how to solve just a beautiful beautiful sudoku as ever from richard i mean there is never a bad puzzle let me know what you thought about it in the comments and um yeah it's just a brilliant brilliant sudoku thanks for watching back later with another edition cracking the cryptic

Channel: Cracking The Cryptic

Views: 192,686

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Id: yEfmuTFq_L0

Length: 21min 43sec (1303 seconds)

Published: Thu Oct 15 2020