The appeal of this puzzle, which has long been popular in Japan and
is growing in world-wide popularity, is that its rules are as
simple as its solution is complex. On a board of nine-by-nine
squares, most of them empty, players must fill in each square with
a number so that each row (left to right), column (top to bottom)
and block (in bold lines) contains 1 to 9. So, in the grid below
you must place the digits 1 to 9 in every column, every row and
every 3x3 box.
After completing the puzzle, number each square from left to
right with a consecutive number. The first row will start with 1
and end with 9. The last row will start with 73 and end with 81. By
taking the numbers that you came up with from the designated
squares, you will find the cache at:
N 7, 15, 0, 27, 33, 45, 51
W 76, 56, 62, 50, 39, 43, 32, 26
CheckSum N = 31 // CheckSum W = 28