Memodoku Game

Memodoku is a small number grid you solve from memory. Every row, every column and every 2 by 3 box takes the numbers 1 to 6 once. The logic is gentle on purpose: the starting numbers show for a few seconds, then hide, and the hard part is keeping them in mind while you fill in the rest. The memory techniques on this site help you hold them.

How to play

1. Fill the 6 by 6 grid so every row, every column and every 2 by 3 box holds the numbers 1 to 6 once.
2. A puzzle starts with a preview of its starting numbers, the givens. Study them. The clock starts when they hide.
3. On Easy and Normal a small dot stays in each given's cell, so you know a number was there, but not which. On Hard nothing stays, and you write the givens back yourself.
4. Your own numbers stay on the board in gold. Only Easy marks a number that clashes with another in its row, column or box.
5. Stuck? A peek brings every given back for two seconds, and the clock keeps running. Press Space or PEEK.
6. Fill the last cell and the clock stops. A full grid that is wrong only says "Not yet", without saying where.
7. Next puzzle deals a new grid at once, as many as you like. Change level goes back to the start.

Choose a level on the start screen. Easy has 16 givens, a 20-second preview and three peeks. Normal, the default, has 12 givens, a 12-second preview and two peeks. Hard has 10 givens, an 8-second preview and one peek. Every puzzle has exactly one solution, and you can always find the next number by looking for a cell that only one number fits. On a keyboard, move with the arrow keys, type 1 to 6 to write, Backspace to clear and Space to peek. Escape pauses.

Scoring

Your score is your time, counted from the moment the givens hide. Each level keeps its own records:

• your best time,
• how many puzzles you have solved, and
• your longest run of puzzles solved without a peek.

Your records are saved in this browser only.

To hold more numbers at once, read about chunking and the method of loci. Or try our other free memory games.