Solving a Sudoku.

[hmkpoker]

Thanks for the puzzle, I enjoyed it ^_^

Sudoku strategy is somewhat similar to minesweeper logic, imho. I went straight to the "evil" ones, which wasn't really that hard. Here's the strategy:

1) Get a piece of paper and jot down the 9x9 board in big squares, marking the given numbers with big black pen.

2) Go through EACH unmarked cell, and list, in soft pencil, which ones they COULD be (eliminating numbers that already exist in the given square, column or row) Be careful to list all and only the correct numbers! This part is very annoying.

Now, we have an outline.

3) Skim through each square, column and row. See a cell that contains a number not possible in any other cells of that group? That's your number. Label it as such, and revise every row, column and square to which that cell belongs accordingly.

4) See a "couplet," as you mentioned? (A couplet is two cells in a square for which you have the other seven numbers figured out). Look at the row or column in which the couplet exists, and eliminate the couplet numbers from other cells in the row or column as possibilities.

Repeat 3 and 4 over and over again, and it'll solve itself.