Kendoku puzzles are built on square grids of typically 5x5 cells (although puzzles having sizes in the range 4x4 up to 9x9 can also
be made). To solve them you must place numbers into the puzzle cells in such a way that each row and column contains each of the digits from 1 up to the size of
the puzzle. In this respect they are similar to
Sudoku puzzles. Unlike
Sudoku puzzles, you are not given any
starting digits. Instead, the puzzle is divided into
Domains which are areas surrounded by a bold outline, and containing from two up
to four cells. Each domain contains a hint consisting of a number and one of the mathematical symbols
+ x — /. The number is the
result of applying the mathematical operation represented by the symbol to the digits contained within the domain. This will provide enough information to allow
each of the digits to be determined. Each puzzle has a unique solution, and no guessing is required.
Any character which is typed at the keyboard will be placed into the focus cell (outlined in red), provided that it is a digit, and is not greater
than the dimension of the puzzle.
The location of the focus cell may be shifted by means of the cursor control keys or by pointing and clicking with the mouse.
Under default conditions, the program displays in each unsolved cell, the set of candidate digits which might legally be placed
into that cell. Whenever a solution digit is placed into one of the cells, the list of candidate digits in other cells is automatically updated.
By the application of some logical reasoning, you will see that certain of the listed candidate digits cannot possibly be a solution
for the cell in which they are shown. Such candidates may be removed by pointing and clicking with the mouse. When the last candidate digit is removed from a cell,
it becomes the solution digit for that cell.