## Step 2: The Basic Basics(scanning)

I most basic strategy to find missing numbers is scanning and it consists of
1)Cross-hatching.
2)Counting.

1) Crosshatching (shown in the first picture). You scan rows and columns to eliminate where a specific number can be in a given region.As you can see there is only one legal place left for the 1(marked green).

2)Counting. In counting you simply count all the different numbers that's in a row,column and region that connects to one cell. if there is just one number missing then thats what should be in the cell. Take a look at the second picture and see if you can figure out the missing number in the green cell.

legend: green = result
red = cause(the cause of the result that is)
This is confusing ????
What!!!???
I don't understand how to determine what number house in the cell
<p>i don't get it</p>
<p>You dont get what?</p>
<p>If you ever get stuck and need some help on a sudoku puzzle, visit <a href="http://www.sudokubeginner.com" rel="nofollow">Sudoku Beginner</a> to get some help.</p>
It is very usefull for those who wants to start playing sudoku.....
<p>Guys, we just created our sudoku app...the idea behind it was that most apps in the market provide poor quality puzzles where each puzzle has more than one solution. However, we did our homework and have tested each puzzle that was included in the game. Hope you guys like it. Please support our android app. Thanks&quot;True Sudoku&ndash;Truly one solution&quot;</p>
<p>WHAT!!!!!???????</p>
<p> expirienced? No... it exp<strong>E</strong>rienced</p>
The best method is to use google goggles app and it'd solve it for you in like 2-3 seconds XD
Great instructable! For beginners with iPhones i recommend the Sudoku app from Pennypop. It makes sudoku so easy to learn, looks gorgeous, and it's totally free.
Nice instructable! I was thinking about writing up something like this, but am about as far from a mathematician as one can get, so I never really got around to it. I call my &quot;rules&quot; the &quot;Two of a Kind&quot; (two of the same number, in adjacent columns/rows that narrow down the placement in the third row of that set of horizontal or vertical blocks), two pair (two pairs in a row, column, or a block, eliminate all numbers in that associated row/column and/or block....three triples is the same, but with three numbers, and I find it more difficult to use this rule, and it shows up a whole lot less, I find; besides, the other rules usually trump the 3-Trips), and &quot;Three-Pack&quot; (all three numbers in a row/column within a block are filled in, this allows placement of single numbers of adjacent rows to be placed in the other two blocks in that row/column of blocks). I find that, with a minimum of WAG's (Wild @rsed Guess), I can usually plow through the hardest level of the Sudoku app on my Droid3 in about 15-20 minutes.
Sudoku is a fun game to get into. all the different <a href="http://sudokustrategies.net" rel="nofollow">Sudoku Strategies</a> can really work the brain. a great past time<br />
I am a beginner at this little brain-tease, and have discovered a solution that will save the masses from the madness of that one grid that cannot be solved; take a black marker and change things to suit yourself.
hehe
Wasn't this instuctable done already? They also suggested the same method
They just seggested scanning,not candidat elimination nor the xy wing
WRT: Step 5 I understand the logic of the numbers but not what you were saying about "x,y,z". Did you miss something out? Cheers, Pat. Pending
the xyz is only to show where the name came from