Sudoku Demonstration - Skyscraper Technique (Example 01)

alright guys before I first kicked this video off I just want to give a shout out to Tiffany on YouTube her user name is Miss Kitty 6 it's mi SS k ity 6 there's only one T in a named Kitty there if you go to her channel click on videos and search for the word pseudo Kuh you'll see some great puzzle demonstrations where she talks about how to solve Sudokus beginner-to-intermediate puzzles what I'm dealing with now is stuff that goes beyond that level and I'm hoping to put more videos out over time but the technique I'm going to demonstrate right now is known as a skyscraper I'm going to show you how to spot one and how to use it to actually unlock a puzzle so that it can be completed so the puzzle you're looking at here right now is one that I solved using the same kind of intermediate and beginner methods that I've used a lot of other people and methods that Miss Kitty has demonstrated very well in YouTube and when you get to this point you can't use those methods anymore you have to use more advanced methods and this is one of them it's called a skyscraper and first thing is how to notice one how to spot one so if you look I've highlighted these four cells and what you'll notice about them is in this column here there's only two cells where a three could be possible and I've highlighted them there and then in this column you have the same thing these are two other cells where a 3 is possible in one of these cells and it forms a shape similar to the x-wing if this was an x-wing this 8 here would actually be the 4th cell and it would form a rectangle or a box but in this case it it's a down 1 so this is what's known as the skyscraper pattern and what's unique about this pattern is because a3 can only exist in these two cells in this column and in these two cells in this column you have this sort of if this then that scenario so meaning if you look at this cell and you say okay if this is a three then a three cannot exist here or here so we could go ahead and mark those as pink and that would mean that this would be the only other spot where the three could exist so you here you'd have kind of that same line across forms one half of the X and if we go if we go back Oh Mia when I exclude that let me go back I'll mark these again so we can see them all as green if we do the same thing we come over to this one and say okay if this is a three then a three can't exist here or here and the only other spot a three could exist would be here and what's unique about this is because a three has to exist either here or here for this top section any other cells that these two cells here can see are can be eliminated as possibilities so let's take a look at this if you look at this cell here and you look from where it can see look straight across this row this is another cell that a3 is possible that this cell can see and this cell is also visible by this cell here so because this cell in this cell can both see this one a3 cannot exist here because the three has to exist either here or here we've already demonstrated that with what I just showed you a moment ago so this three here can be eliminated and if you look the other direction starting from this cell if you look across here and see what other cells have a possibility of a3 this is the first one but notice that this cell here cannot see that so we're not going to worry about this one right now it can't be seen by both of these cells but if you continue on and you look these two cells here can be seen by this one and they can also be seen this one so again these two cells here can be ruled out as a possibility of a three so now that we know that we can go ahead and highlight all three of these and say exclude threes and if you notice and turn off all my color formatting here you can see that here's two naked singles now so just from spotting that that skyscraper and then using it to our advantage to exclude possibilities where other numbers can no longer exist we've completely unlocked the rest of the puzzle now if I go through and I just mark where all these singles are that we just spotted we're going to be able to complete the puzzle very quickly there you go thanks for checking out my video guys

Channel: Shuey187

Views: 204,456

Keywords: 数独, Sudoku (Game), Puzzle Game (Media Genre)

Id: VeEu03u9pUs

Length: 5min 20sec (320 seconds)

Published: Sat Dec 28 2013