## Help with next move

Advanced methods and approaches for solving Sudoku puzzles
Take a look here and here

S
simes

Posts: 324
Joined: 11 March 2005
Location: UK

Sorry, but I still don't understand

could you explain me this as i were greenhorn
wuem

Posts: 3
Joined: 23 August 2005

If you look in row 2, you see that the only ones are in box 3 (columns 7,8,9 -- in this specific instance, columns 8 & 9 only). Since there has to be a one in row 2, then it must be one of those two. That would mean that you could exclude all the others in box 3. Hence, the one in r1c9 could be cancelled.
Dusty Chalk

Posts: 21
Joined: 15 August 2005

You are absolutely correct. Thank you so much for your help.
dpletcher

Posts: 17
Joined: 20 August 2005

It is so obvious. I was probably blind yesterday....

Today I see. You have worked a miracle
wuem

Posts: 3
Joined: 23 August 2005

The question is why can we eliminate 1 in R1C9. You will note there are 1's in R2C8 and R2C9 and with no other 1's in R2 one of these squares must contain the 1 for box 3 therefore you can safely eliminate the 1 in R1C9 . This scenario is what is meant by "possibles locked to a row " . If you can establish a certain number is confined to one box in a row or column you can safely eliminate that number from all squares in the other rows and columns squares in that box . Clear as mud!
Ianac

Posts: 6
Joined: 07 August 2005

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