About Gridoku™

Gridoku is a logic puzzle based on the logical placement of letters within a square grid. A game of pure logic, Gridoku does not require any calculation or advanced technical skills — all that's needed is practice, logical thinking, and concentration.

How Do You Play Gridoku?

You start with an empty square grid. There are five levels of difficulty:

• Easy — 3x3 grid
• Medium — 4x4 grid
• Hard — 5x5 grid
• Expert — 6x6 grid
• Evil — 7x7 grid

The square grid is always initially empty.

On the keyboard, you'll see a certain number of letters — say, A, B, and C. The number of letters is always less than or equal to the number of empty cells in each row or column, with a minimum of 3 letters. For example, in a 4x4 Gridoku, the number of letters may be 3 or 4. If the number of letters is less than the number of cells in each row or column, then each row and column will have a certain number of empty cells. In any event, each letter must occur once and only once in each row and column.

There are certain clues given outside the square grid. The more clues, the easier the puzzle. Each clue must match the letter closest to it in that row or column. For example, if there is a C as a clue at the top of a certain column, then in that column, C must be the first letter from the top (it may or may not be preceded by one or more empty cells) — but an A or a B cannot appear in that column before a C from the top.

One cell can contain only one letter — it may be empty if the number of letters in the puzzle is less than the number of cells in that row or column.