HOW TO PLAY
       Sudoku is a fascinating game of pure logic that involves no math
whatsoever -- and no guessing. Using the given numbers as guides, fill
in the grid so that every row, every column, and every 3x3 framed box
contains the numbers 1-9 exactly once. The solution to each puzzle is unique.


TIPS ON SOLVING -- "The Three Strategies"
       (1) Intersections: Pick an empty square that's the crossing point
of a row and a column that already contain as many different numbers as
possible. Usually this will narrow the "possibles" for that square down
to just a few numbers. If it narrows it down to one number, just write
it in. If there are several "possibles," pencil them in at the bottom of
the square for future reference.
       (2) Box Stripping: Look at any set of three-in-a-row framed boxes
-- like the top three, for example -- and see if two of them are showing
two numbers that are identical (like a 6 showing in Box 1 and a 6
showing in Box 3). Notice how this number is thus ruled out in all but
three squares of the third box. Already existing numbers and crossings
may narrow the choices even further.
       (3) Twins and triples: Whenever you've penciled in two identical
possibles (such as 4,5 and 4,5) in a single row or column or anywhere
within a framed box, they constitute a self-contained "twin" and those
two numbers are thus ruled out from appearing anywhere else in that row,
column, or box. Similarly, if you've penciled in three different numbers
as possibles in exactly three squares (such as 1,4 and 1,4,9 and 4,9) in
a single row or column or anywhere within a framed box, they constitute
a self-contained "triple" (1, 4, and 9 must go in those three squares in
some order) and thus they are ruled out from appearing anywhere else in
that row, column, or box. And in the game of Sudoku, knowing where
numbers can't go is just as important as knowing where they can go.
       NOTE: The Three Strategies have a few subsets, offshoots, and
shortcuts, but you'll discover most of them on your own (and that's half
the fun).

Happy solving!

Merl Reagle