Hi, I am new to these message boards and fairly new to sudoku. I was doing one of these out of a newspaper the other day and after 2 or 3 hours i had it all filled out and then i realized that i had one number wrong, so the whole entire page was wrong. Being a computer science student, i realized that i had just spent 2 hours doing what my computer could do in a fraction of a second, and i havd screwed it up. so i decided to write a sudoku solving program (in JAVA).

My question is as follows:

-is every legitimate sudoku game, say from a newspaper or a puzzel book, entirely logically solvable? or do you reach a point on some games where you have to make a guess?

I haven't played enough games to know this for sure but i'm guessing that they can be completely solved by logic. However, any input on this would be very appreciated. If i have to write my program to guess numbers when it gets stuck it will be much more difficult to program and solving time will be much greater!

Cheers!

Swordfish