Today's Dragon Tip

Striped Sudoku
Why not try our own new puzzle type - the Sudoku Stripe? Somewhere hidden in the puzzle is a set of consecutive numbers that you can make use of when looking for the solution.
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Coloring Sudoku Squares [Page 11 of 14])

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To keep track of squares on paper and pencil is easy, you can mark a square and rub it out when no longer needed. Sudoku Dragon offers color marking that lets you easily put a temporary mark on a square. There is a command to quickly clear coloring from all squares in one go.

The colors are added from the right mouse menu or the Edit menu or, using the keyboard SHIFT+Function key.

In this example puzzle screenshot, coloring has been used to identify squares that can take a 5. Alternate pairs have been marked with different square colors. Starting with orange square Bg this is paired to turquoise square Hg. Only one of these two squares can be the '5' in column g. Next Hg is paired to orange square Ii as a pair in region Gg. This square is in turn paired with turquoise square If. In addition there is another pair Bd (blue) and Fd (red) in column d. Having marked the alternate pairs it is evident that square Bf (lime green) can not take a 5 as it is in the same column as a turquoise square and the same row as an orange square. If the orange squares are correct then Bf can not take a 5 but nor can it if the turquoise squares are correct. As either orange or turquoise must be correct and not both must be correct that proves it!

You can use coloring just to remember particular interesting squares. Together with the square annotations coloring is a useful feature.

Give the SudokuDragon a free 23 day trial by visiting our download page.
One of the very few Sudoku solvers that gives you color marking.