Tutorial #50 Solving a hard puzzle from the beginning to the end

[Applause] hi everyone here we are again Robin the Sudoku guy with a special tutorial because this is tutorial number 50 and I'm gonna make it a special one because I've had several people request that I actually do a full puzzle that is difficult so let's hope we can do this you know over the years I've noticed so many people calling difficult puzzles all kinds of names I'll give you some challenging diabolical evil very difficult super fiendish black belt and and so on all difficult puzzles require the knowledge of a lots of techniques and tricks if I had six people doing asunder same puzzle I can guarantee that they all will take different routes because it depends on what you know on what you see and win let's see what happens on when I do this one you probably see the things that I missed out that you see before I do that's quite a possibility so let's have fun hey here we go in this puzzle my first look anything that stands out very quickly and here we have the top three blocks and I see there's nothing one nothing to number three five has got two so we know that in this block there could be three fives put in here little numbers but you know this becomes a debate should you put the little numbers in or not some people say I don't put any little numbers in some people say I put numbers in because it helps you choose this particular time I'm going to leave it empty just for fun so we know it keep it in your memory it's good for memory tutors pseudocode is 3/5 you could go in there one of those is going to be a 5 let's push on now to these three blocks anything that stands out very quickly nothing more 1 and everything with 2 or with two here's in this block here we cross to do a cross meet tempest system we cross this two and bring this to down we finish that with two spots for two now this is something that's very very important because I find a lot of people still making this mistake if a little number can go in to cells of a block row or column put them in if a little number can go in more than two cells but is not in a row particularly or a column within a block then don't put any numbers in remember that I'll repeat that more than once I'm afraid so let's look at this now too if we got two to three we got a three here okay now we've got top bottom middle and now let's go four five six we have a 16 or six years so that means we have a six here and a six here it only goes in two spots or put it in six seven eight well nope see this eight if you go across it cannot be in here in this block but he has to go nowhere else but up there now that means that we couldn't have eights in here in a row now this particular time just for fun I'm going to put the little 18 be just to see what happens okay now let's see what we've got here oh here's something in this block we've got a 3 by 3 and the 3 by 3 simply means if there's only three numbers left in that block and they'll have to go in these three cells if I look carefully it is what's missing it's a four and it's five and a nine oh here's a four and here's a nine so that has to be the five and what that does it makes these two cells a matching pair because there's only four nine left so we have a 409 and a 409 where that was neat okay now we that's done for these three blocks now look at these three blocks there's nothing for one two three yes we can do a three top little bottom with this three here that three there this can be a bottom great for nothing five nothing six seven eight nine can have and can possibly go in two spots so we can put it in there okay now let's really do the vertical blocks in here once and I'm seeing their two serves anything their threes yes there's a possibility of three Center right left we can have it here but because of that three we can't ever get we could have it there either one of those two spots now remember the five cannot be there anymore it's going to be your one of these two okay now let me see anything else in there no I think we'll go to these couple blocks now once no twos no threes threes no yes threes there is set up left and a right and it goes up there now we have a middle at the top and a bottom so this becomes a real three and we can erase this three Pham that was good now what does that mean we're ramifications of that first of all we have here a five so can't be a five there we remember we had in our memory five could be along here if it can't go there it must go there now what's the ramification of that well that's the center that's a right there has to be on the left here so we can go here whoops no small lettuce because I see there's a fire there small ones small numbers of meat or small on there that's important again I put it in because there's only two places a fire can go six seven eight no we now do these these vertical blocks once no twos three we did three didn't we for a fork ago you can't go there because of this force rule of exclusion there there there I could go all over the place so leave it five six seven Oh five six look at this this is neat this five six means that the five six can't be in this block in this spot here and there's only two spots left otherwise so this becomes a matching pair matching five six nineteen five six okay neat now when you do that again this will now become a three by three what are the numbers now what is missing in here well we don't have a one in here and it can't be there so we put a one in here and one in there too took me and put a two in there and a to there and there to there there's got to be one other number that's missing in this block it's an eight so we'll put the eight in there and that means that only one tool right can be in this block there and up in here so that means with the rule of exclusion we can get rid of this eight okay goodbye and so you're left with a matching pair well that was neat let me see now having done that what's left we have a nine we have a good have a nine in here for for now the four can't go in here has to go over there so this will be a four nine matching pair and if that's a four line matching pair we're gonna have to have a four in here some way to spots that can going well isn't that neat okay we've got all night I will do these three thirty four blocks fives or the five could go 10 to 20 with about two three we've done the two twos no - no okay so let's go to yes the fire could go there or here right center left it's got two spots we can put it in notice if you notice anything else in there oh yes I do I miss the ones here's the one there's a one this has to be a 1 now having done that our next step is to look or a row column or blocked it's only got two empty cells left well these two cells are spoken for therefore these two empty cells have to be another matching pair and they would be a two and a seven well if there are 207 matching pair yeah why put it in we merely know that that can't be a seven so we'd make this a 2 and this is 7 now what's the ramifications of that let's take the two the two - yeah we're right when we did the cross meet system that worked out real - and 7 right center this has to be the 7 now this is neat we now have a 3 by 3 plus a matching pair well plus 2 empty cells the rule is and I'm going to put this up as a clip the rule is a 3 by 3 + 2 empty cells it means that those two empty cells have to be a matching pair and we found that out by using this system as well there's two ways of solving that one but here's something that is really neat it's another little rule if you look at this block there is two matching pairs plus two empty cells the same rule applies to omit and matching pairs plus two empty cells means another matching pair which you can have in quite often in difficult puzzles so this would be what numbers are missing in here or so one is missing one can go there in there and the other one would be 1 2 3 4 5 ok so we have a matching pair fun now what does that do immediately because of the rule of exclusion this cannot be a fine if this is a 5 and that's a 5 the 5 has to be this one so that means we can make that a 5 but what's the value of only putting in and not numbers in to cells if that's a fire to could only go in to cells so this becomes a to great system now having done that a check top bottom middle Wow isn't that neat now if I look at this row we really have two empty cells one has got four nine in the other empty cell has to have a four nine in it too it has to be a matching pair its matching pair plus two remember that rule for nine put that in now you see while I'm in this area I see that there's only three cells left in that block let's see now we have a four for looking up and down seven seven and seven seven Anna knowing there's no nine up in there so no seven or nine and through here okay well we don't have to see what happens here great now we come to the stage where I'm looking for a place where there's only two or three left two or three empty so it was left in a row column or block I think I'm gonna have to go to four now we're going to use outside the puzzle now outside of the puzzle is a system that I teach for beginners but as you get more more advanced you should be able to remember four numbers possible it's possibly without having to write them down the bottom here and I'm going to do I've decided I'm going to do this one here there's four spaces and therefore numbers we know it's a four seven and nine that's going to be one other number of one for it's a six okay four six seven nine okay here's the DES for six in here this is a seven nine so we just leave it as the four six four there's a six here some kind of a six theta so here we have a boy is the four nine so that has to be a six seven and down in this one here is it's a four there's a nine already so it's a force except now looking at that I don't see anything that's really standing out to help us this stage so let's find another row column or block to something before do you there's quite a few of them let's try this one because there's lots of numbers up here compared with almost yeah we'll try this one anyway what's missing along here there's four numbers missing instead of putting them out here I'll just put kick him in the head there's a one missing a one [Music] before they're fine one six there's a six here seven and eight one six one four six and eight so one four six this is a white okay this is a one four there's a six up in here so there's a just one four eight and this one here is a one four company of six is the six down in here so it's a 4 a so we now have the missing numbers in small numbers that is in that row let's look at it what is there oh look you may have noticed this already this is neat see this row has only got one six possibility so that means that this becomes a six if you want to know more about this I've got a lesson I think it's lesson 13 where I said there's only one place it can go well in this row the only place a section can go is there and that's a neat discovery now I haven't done that what are the ramifications well let's just take the sixths first there's a six up here there's a six up there we could have a six here or here going down this way we could have a six here right the center of it we're going over six there good now what's the also the ramification of that six let's look at this we come down here that six is gone and this six is gone and what does that do that means that this becomes a seven okay that becomes a seven let's look at the ramification for that seven we have a center top bottom one of these is the seven it can't be there so then one of these are the seven so we can put it in seven this gets rid of that seven now if you look at this book look at this if you look at this block there's only one place for seven now and that's right there so that's great put that seven in okay and that seven means that one of these is the seventh in two spots we can put it in now down here we can get rid of this seven but that mean makes it this one a four now what's the ramification of that one this six is really giving us a lot for the four means and we will go up and do this area first we'll go up that means that this becomes a nine and that nine means that this becomes a four wow this is this is this is exciting because what's going to happen here is all kinds of things I think we'll see that becomes a fourth this for here is eliminated so this becomes a nine and that nine means that this is eliminated and that becomes a four okay boy isn't that neat if that's that fits because here we have a middle on the top and the bottom one of these are going to be four that fits it that's great super now we don't need to look a new number down here was a four wasn't it before we know that a four is going to be up in here or there this for going this way means that this one here can't be there because of that for this one here becomes a four and look at this therefore this therefore that was the plan of got it and then this for here becomes a nine and that becomes the fourth okay so that becomes a nine and this becomes a four we things that block already fantastic if that's a nine and that's a nine this becomes a possible nine and that becomes a possible night there's two spots we put it in but when we remember we had to sneak we remember had a five hand of five years of possibility but once it the five has gone from there this becomes the real bit five now anything from here okay I can immediately see oh look at this this was amazing this different the different ways to go I could say this five means that this becomes a six or I could say this five means that that's the because we have a bottom the top middle well I'll go this way just to begin with that was a far so this becomes a six which means that this becomes a fine so what's what's the ramification of that let's take the six first well that six can go there's six you're down you're going to spots there so that means that this has to become a six okay now what's the rim of the canyon are there six six six is the six can come in here Wow now we put a six here well let's do the five first but it's the five here that means that this becomes a 1 and this becomes a 5 both things are really happening here five now because of this six this becomes an 8 and this becomes a six and we put an 8 in the six in there with finish that block already six six six six to the fifth five self-checking five five five four four one of these to the four yeah well when I went up there on the notice this look at this there's only one left that's easy one it's a one okay what's the ramification of that one top middle oh that becomes a 1 and therefore this becomes a full right and we now have a matching pair in there oh let me see is there anything else with four yeah let me see here's one two three we have a two four eight in here too too too clumpy or four to eight my pen is starting to run out there two four eight does that give us anything No let me look at their they say this one here one two three four was one two three in that there's only two free in there we're missing a well when I did that too and on that two of them I didn't put in a two here did you notice that you'd probably be saying hey Robin you missed that yeah I did maybe we kept it later okay so we've got two eight nine we have an eight here we have an eight there - eight nine is annoying over here and we have an eight we have an eight there because there's a two and there's a nine okay if we have an eight there that can go and that can go so this becomes a 2 well I'm discovering things all the way along here okay let's push on if that's a two this two can go and Wow we have a - any nine okay just for fun I'm going to do this column here there's only three left we could do it this way as well okay let's try now what's what's missing in here 1 2 to 7 and the night so - 7 thank oh look what I've discovered - wait - wait they are very valuable - seven eight well guess what when we put that out in we can get rid of that 8 and we missed that one didn't we so um this to eight very powerful very powerful - it means that any toy belong here or ain't you all right along here it can be eliminated so you can get rid of that too now let's see rule of exclusion therefore this becomes a nine that makes sense too because we've already got the two there now what we got here we where we have to okay we go to one we're getting down to the end in this particular three there's only three here it's a one two and a seven well there's a seven minutes one - that's right we have a one up here so it's a to seven we have a one here there's only a seven there and we can't never want it we have a 1 and a 2 here so that means that this becomes your 7 and that becomes a 2 okay then we will really come quickly now 7 and that becomes this becomes a 7 very good if that becomes a 7 this is gone that becomes a 7 up in here okay I wonder what that does now one thing fencing okay we'll have to sing after as we go let me see now I think that could be a 9 yes Center right 9 yep which means that this 9 can go and now we've got four left in here my three left in there let me see it's a two well if this is a - look at this this is the - this becomes a 1 I missed that one if that's a 1 make it a little darker it's actor 1 this becomes an H to get rid of that one there that becomes the night look at this therefore this becomes a 2 well we've gone like a crazy here and this becomes a night with our long house done it becomes an 8 well that whole road that whole column is done okay now what we left in here we've got 2 left in here what are the numbers there are two left in here in this block around well we have a 1 1 it has to be a 1 1 look ones already there so that means that this becomes a 6 and this becomes a 1 then let's look at the ramification of that 1 1 1 yeah this one 6 6 6 has to be up in here it could be here or here but it can't be there so it has to be there okay and this six means that this six is eliminated oh wow now in this column we're getting to the end now it's going boom boom boom boom that has to be a two because that's the only one left in that corn if that's a 2 and that's a 2 this becomes an 8 and this big image will get rid of that 8 that get rid of that it becomes a 4 that becomes a 4 therefore this therefore we've got this becomes a 2 because you've got top middle bottom okay and we're down to the last bit here this 4 means that this becomes a 1/8 okay and that becomes a 4 so that completes that block and we've done got one left along here well look at the nines who knowing we're gonna learn in here so it's 2 lifting this over these 9 9 this has to be a 9 so we finished that as well and now what have we got left in here I think it's an 8 bottom top middle that's a night and do we have recovered it yeah whoopee we covered it well I can put a little smile up in here I don't know if that fits but we've survived solving a fairly difficult puzzle I hope you enjoyed that there's lots of techniques we used lots of tricks and I hope you learned something at the same time

Channel: Sudoku Guy

Views: 164,970

Keywords: Sudoku lessons, sudoku tutorials, sudoku techniques, sudoku tricks, sudoku hints, sudoku for seniors, sudoku for the frustrated, sudoku for the family, sudoku for beginners, sudoku for advanced, sudoku for dummies, how to solve sudoku puzzles, how solve sudoku, brain fittness game, I want to learn sudoku, Learn sudoku, sudoku

Id: RsO2rxKoRHw

Length: 26min 4sec (1564 seconds)

Published: Wed May 22 2019