Nintendo Sodoku Gridmaster Instruction Booklet page 9

SUDOKU RULES AND STRATEGIES
Sudoku Gridmaster is based on the Japanese game Sudoku. The rules
here are the same as those used in the traditional game. There are some
special rules available, but we'll cover the basic ones here.
RULES OF SUDOKU
There are only three rules:
1 You can only use the
numbers 1 through 9.
2 Each columns (∂) and
rows (∑) can contain no
more that one of each
number from 1 to 9.
∑
3 Each 3x3 Blocks outlined
in bold (∏) can contain no
more than one of each
number from 1 to 9.
By following these rules
and looking at numbers
that have been placed
already, you can figure out
what numbers to put in the
empty spaces.
∂
∏
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DEDUCING THE SOLUTION
Search for missing numbers
within the Guidelines.
Look at the picture on the right and try to figure out
which number should go in the highlighted box. It's
simple, isn't it? The only number not placed in the
Guidelines is a 1. Therefore, the answer is 1. In the
same way, you can determine that the number that
goes in the box on the top left of this block should
be a 9.
Use options when you can't decide.
Now look at the box on the bottom right side of this
block. You can't narrow down the answer to a single
number here, so you should enter the two possibili-
ties, 5 and 3, as options in the same box. Your
options appear as small red numbers inside the box.
In situations like this, options come in very handy!
Solving one cell can lead to another.
Now look at the bottom left box in this block.
Because you solved the upper left box with a 9, you
can see that a 3 must go here. Therefore, the box
you listed with the temp numbers 3 and 5 must be
a 5! The last box in the middle must therefore be a
7, and the block is done!
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