GRE friend I will show you my favorite stoku trick that will reduce this puzzle by my Friday featured Setter to only one Advanced strategy click below if you want to give it a go and with that it's solving time all right to set this puzzle up there is a few little things you need to add to it to make it the right setup okay we got these sixes column one and Row one makes the sixes in two spots here this is called matter notation anytime a 3X3 block you have two possibilities for a candidate you can mark it in case you solve one of these cells you can solve the other one right away these sixes also act as a pointing pair and so since they have to be in Block one somewhere and they're limited to row three they cannot be anywhere else along that row so that means sixes can't be there they can be here and they can now down here in Block six with these two sixes they can be here and so what you notice is that the sixes are kind of like this mini X-Wing so now they're restricted to column 7 and N in blocks three and block six so that means that the only place where six can be in Block nine is in column 8 because it can't be in any of these spots okay so we set up a lot of those sixes now if you're working on this you notice there's a 3 four in row two and there 3 4 up here in column 8 3 four are limited to these two spots and so I'll mark that as a hidden pair since the three and four have to be somewhere here in block three limited these two spots no other cans can be in those two cells you can do the same thing over here in Block two with the ones and twos you got a one a one two here you got a one two here the only spot you can put a one and two block two all right there you thought you know this might help you out with the solve it helps later it doesn't help right away but we do want to Mark those spots and then you got this nine cutting across got this nine coming up the nines are limited to two spots and block four makes them a pointing pair so they can't be here Nine's got to be in one of these spots okay and then fours since they cut across here and they can't be in these two cells they become a pointing pair that's where the one and two come in handy right now and so the one the fours are limited these two spots they can't be anywhere else down column 4 I'll show you where that comes into play one of the things it does is now it restricts what can be in this cell this cell can't be a 1 2 3 can't be a four because of a point pair it could be a five or six but it can't be a seven eight or nine okay and if you look at this cell right here this can't be a one two 3 four it can be a five or six but it can't be a seven eight or nine they all see the cell so you have a nice little naked pair 5 six right here which limits these three cells now to a 134 naked pair right because 56 can't be in those cells anymore you can get rid of the three from there you get rid of the four from there I wanted to point that out so all these are nice little setup but you notice we haven't solved a cell yet and it's pretty hard to solve one cell here but I'm going to show you that neat little trick and you might notice and what I popped out to me when I first saw this is the way the digits were set in rows 2 and six and I mainly thought of my favorite brick and so to set this up let's see what could be in these two rows okay this can't be a six or nine but it can be 1 two 3 four cutting across can't have five six here can't have an eight there uh you can't have 78 there and you can't have a 789 there okay let's look across row two looks like two 7 excuse me 6 789 right 6 789 this can't be a six or a nine okay uh you can't have the six is here can't have an eight there all right and you look here you can't have a two you can't have seven and you can't have a nine okay and then you can't have a 7 8 9 okay so we we got some bvcs going on here and we want to further restrict these cells how can we do that well let's mark all the rows that contain 1 2 3 4 let's mark all those rows up and we're going to color them blue all right then let's cover the rest of the columns with the remaining digits that we can see here you know you got predominantly 1 2 3 4 in the blue and you see a lot of 6 s 89 and one I'm about to Mark here okay and we're going to remove all these funky colors here where there's double colors you don't need that and I'll explain that to you in a second this is my favorite trick this is really really cool so what we know is that in the blue you know these rows that contains a set of the digits 1 through n and so row two six seven and eight all contains you know one set of digits for 1 through n so we have four sets of that so the the blue set the blue group contains four sets of digits 1 through n you look at the orange there's five of these columns that I marked so they would contain five sets of the digits 1 through n so what I'm going to use is called set equivalence Theory and what it helps us do is figure out of these digits that are in the orange where can they be in the blue so what we know is that whatever you have an intersection like these cells they're going to be the same in the blue group as they are in the orange group and so we don't need to worry about those they're going to be the same and then you notice there's some digits that's blue and orange you can remove those because so this blue digit here represented by the Orange right there this orange digit can be represented by Blue right there so we can find a spot for those and then with these fives same thing you don't want to worry about those what we did though is we created this huge restriction right here there's only five cells in the blue we don't know about and they have to be and contain since these are only one twos threes and fours they got to contain some combination of these six sevens eights and nines it's a little unfair though because if you count all these digits you get 1 2 3 4 five six 7 eight well there's eight of those you can't fit eight into five what's going on well remember we have five sets in the orange group and only four in the blue so to even things out we if we grab from that fifth set the 6789 extra because we're looking at a set of digits 6789 here and then in blue looking at digits 1 through 4 so if we grab this extra 6789 remove it then that means in four of the sets of the orange you still that would be equivalent to these four sets in the blue and so what we know is now these four digits the two sixes the eight and nine have got to be somewhere here in these five cells they have to be plus we have another digit we don't know that fifth digit is this is what makes this puzzle so intriguing you think well we can't we can't figure this out we have this extra digit it could be one through n that's not going to help us ulate but it is because there's got to be two sixes and only one nine you're going to see quite a bit of restriction here the ninees got me in one of those spots the sixes you know they got one of them's got to you know could be in here or they could both be in those two spots let's see what goes on here so if you have a one two three you can't have a four in that cell because of these fours you can have a five six or nine in this cell right here could this be a five this is what you got to ask yourself if this is a five then you know that the since there's two sixes in these cells one of those sixes is going to have to be here actually would have to be there because if you put a six here and blocked it out you don't have another place to put the other six the sixes would have to be in those two spots the problem comes in is where would you put the nine in the blue we know at least one Nine's in the blue and since now you've took these two cells where the nine could be nine can't be blue so we know this cell here can't be a five can only be a six or a nine if you put a nine there that's cool because then you you could put the six here and here if you put a six here then you could put the nine there and you could put the six in one of these spots so we're good the 69 has to be there this is the first big deduction you got to make now we come over here that this cell what can we deduce about this cell well we know it can't be a 1 two 3 or four or seven could be a five six eight or nine same issue goes on here though if we try to put a five or an eight here let's say you know we put a five there now we know we got to have two sixes over here so one of these this would have to be a six and then you put a six in one of these two cells well where does a nine go nine can't go in those cells you block it out same thing if you put a nine there you'd have to put two sixes in these three cells we can't do it so we know the five can't be there and it's the same thing you put the eight there same thing it crams one of these six or nine in there and then the other one won't be able to fit in those blue cells this is awesome I've not seen an application set done like this what it gives us is that we can eliminate the five and the eight and you can go further on go that uh you can have exactly one six and 1 nine cuz one of nines has to be here it can't both be nines because then you wouldn't have a spot for your two sixes and they can't both be sixes because you'd have no spot for your nine so it's got to be one six and one nine and this is exciting stuff because we're going to be able to make some solves and so I asked odish about this puzzle you know how long does it take you to set s dokus and answer is anywhere between 3 and 20 hours to set wow it's a lot of time on a puzzle depend on unique us in a difficulty he really wants to be good quality and I've noticed that he'll test and re work stuff to make it even better and he says normally for a classic that's six to seven hours a little bit more for some of those variants he's just got to have an idea to work with first while I love the idea that you put into this also love the ideas that some of my great creators of puzzle packs put into their puzzle packs so if you want to get my latest puzzle pack you got to be a member of smarty party click on the pinc com below and join and you'll be supporting me to make better content and you're investing in the future of smart Hobbies all right I want to get rid of these extra blue and orange because we don't need the rest of this we're not going to figure out what goes in the orange we're just going to figure out and remember that those five cells got to contain 1619 so you got a 68 and some other digit in here that's what we got to remember this is interesting stuff first thing we do since we removed an eight from this cell and you have this eight cover in those cells Eight's got to be one of these cells here in Block nine it's a pointing pair eight can't be anywhere else along column seven so we can remove an eight from right here and solve that now for a six which allows us to solve this cell for a two and we're going to be able to remove this SNY Mark and solve this cell for a six awesome all right after solving that six uh you'll notice now seven in this point pair of eights and this eight and seven limits 78 of these two cells and so then we have a 78 hidden pair and a 135 naked pair right there okay and now with this two you can remove these twos and you end up with this nice 79 naked pair okay and so you have a naked pair 79 here in column six what does that do for us well since the Seven's got to be one of these two cells it can't be in those cells you have these two sevens we can solve for seven right there nice and now you remove the sevens from here now you have an eight n naked pair in this column and so the nine is got to be either here and here or here and here right The Nine's got to be part of this naked pair in these two so a nine can't be in these cells anymore this now has to be your nine and by using that set equivalence Theory we can solve this for our six we know that's got to be the six which gives us the five here and the six here then remember using this six now we can solve a six here this has got to be an eight and some other digit that we don't know about but remember there is still an advanced strategy all this is going to reduce us to one Advanced strategy and we got a little bit of time before we get there you got to keep watching and you love solving puzzles like this then subscribe to Smart Hobbies share us with someone you know who you think will enjoy it as well let's get rid of these colors because we won't need that I'm just going to Mark these at eight got to be one of those two cells since they have to be one of those two cells in set equivalence the this can no longer be an eight and so this has to be your eight and now with this nine and this nine we can for nine here which gives us a 14 naked pair awesome and the 14 naked pair gets rid of the one right here and wait for it wait for it because these fours you can eliminate the four from right here and you get three in the corner yes there we go all right and now you got your four right here which displaces this Snider four and allows us solve for four right there awesome and now what you can see is with this five the only place left for a five and block three is right there which gives us a 29 naked pair and with this four we can work our way down this column okay we need a four uh we need a 5 S8 I got a 58 here so that's got to be your seven and then got to be a 58 there well with this three this is going to be your five gives us a one three there this now has to be the eight and that's going to be your five and with this eight that's the seven and that's the eight so we just did all that great solving there awesome and now at this eight you're going to unravel few more solved cells that's a nine that's a seven that's an eight and now with the five and the eight this is a seven here's your nine here's eight so we solved all of that we're not done yet we're still got an advanced tra it's going to block our pth path to get through this whole puzzle but we just solved so much stuff now all right with this five we going to five be down here and block eight five's got to be right there right and now after solving that five let's look with these twos we can solve for two right here nice with this six just place that SN 6 s for six right there looking good awesome and now we got this seven and these two sevens we can solve for a seven here with these twos we can solve for a two here displacing that SN n okay and what you'll notice is we got a one 14 remaining here and this is a spot where you're going to get a little stuck all right if you keep going in row five here this cell can be a 13 4 right we got a 134 naked triple across row five you come down here to row 9 you'll notice that the fours are limited to two spots there right and the fours are limited to two spots in row five but in row five and row N they share the same column column five the tips are in different columns but in the same three Block band let me Mark that up and so we know that these are a conjugate pair either this is a four if that's not a four that's got to be a four conjugate pair either this is a four and anything that sees it can't be a four so this cell cannot be a four it's not a four this cell has to be a four it's the only other spot in row five for a four which knocks a four from here it makes this cell a four so if this is a four nothing anything see it can't be a four if it's not this has to be a four they both could be fours but now we know since one has to be a four we can eliminate a four from any cell that these both this is a sodoku skyscraper this is the only Advanced strategy that you need to solve this puzzle if you know my favorite trick and what it does is it eliminates a four from right here and eliminates a four from right there and since you have a four here the only place to put a four is right there and then this has to be your one you want to learn more about skyscrapers check out this tutorial what we can do is now solve this for a four which makes this a one that's a three that's a one that's a three awesome and then what do you have here it looks like we need a two or a four and we'll get to that what we can do is we can eliminate three from right there which makes this now a three awesome all right and then what we got here is is I said the two four boom and then we move on and then this one now we put a four right there so there's actually a four in both of those and then this is going to be your one and with this three that's got to be your three that's got to be your four let's get rid of these colors thank you so much skyscraper for helping us out with this puzzle and with this four now that's a one that is your four and with this four this is a two that's a four that's a two that's a one this is a nine this is a two I love to disambiguate those bvcs okay what we looking for here looks like a one and three got my three there so here's your three here's your one with these two ones this has to be the one I need a 58 here here's my five so here's your five and here's your eight and with these two eights we know this has got to be your eight with this nine this has to be your nine and the last cell is a five set equivalence theory has some other fascinating applications like in this video please support me through my buy me a coffee page I'd really appreciate it thank you aish for this wonderful sodoku and thank you so much for watching