How to Play Shapedoku: A Simple Guide for Beginners

The goal and the three rules

You start with a 9 by 9 board that is divided into nine smaller 3 by 3 boxes. Some cells already hold a shape when you begin, and these are the locked starting shapes, sometimes called given shapes, which cannot be changed. Your job is to fill every empty cell so that the whole board is complete and correct. There is no math involved and nothing to calculate, so if you can tell nine shapes apart, you can play. The rules are simple and there are only three of them: every row must contain each of the nine shapes exactly once, every column must contain each of the nine shapes exactly once, and every 3 by 3 box must contain each of the nine shapes exactly once. That is the entire game. No shape may repeat inside the same row, the same column, or the same box, and when all three rules are satisfied at once across the whole board, you win.

How to place a shape

1. Tap an empty cell to select it, and it will highlight to show that it is active.
2. Tap the shape you want from the picker below the board.
3. The shape drops into the cell, and if it breaks a rule the board gently flags it as a mistake.
4. To change an editable cell, select it and choose a different shape, or use Clear to empty it again.

A quick first move

The easiest way to start any board is to look for a row, column, or box that is nearly full already, because a nearly full group usually forces a move. Say row 1 shows eight shapes and only the crescent moon is missing, with the single gap at r1c6. Because every shape appears exactly once per row, the moon can only go in that one empty cell, so you tap r1c6, tap the moon, and it locks into place. The same logic works for a box: if the top-left box holds eight shapes with one gap at r3c1, the missing shape has only one legal home. Hunting for these almost-complete lines and boxes is the whole of an easy board, and each shape you place tends to reveal the next gap that can only hold one thing. Follow that chain and the grid fills itself in front of you, one certain move leading naturally to the next without any guessing. On harder boards the chains run out sooner and you will need notes and a little patience, but the starting instinct never changes: always look first for the group that has the fewest gaps, because that is where the board is most likely to force your hand and hand you a free, certain placement.

Using notes

When a cell could hold more than one shape and you cannot yet prove which, turn on Notes mode. Now tapping a shape adds a small pencil mark instead of committing a final answer, so you can record the candidates for a cell without locking anything in. Notes let you track possibilities across the board and see its structure instead of holding everything in your head, which becomes essential on Hard and Extreme boards. When you later place a final shape, Shapedoku can automatically clean up notes that are no longer possible in that same row, column, and box, which keeps the grid tidy and saves you from erasing them one at a time by hand. You can turn that cleanup off in settings if you would rather manage notes yourself, and you can always add a cleared note back whenever you want it, so the feature helps without ever taking control away from you.

Hints, mistakes, and difficulty

Stuck on a tricky board? Use a hint to reveal one correct cell, with the first hint free each puzzle, which is a gentle way to get unstuck without giving up. In classic play you have room for a few mistakes before the game ends, so you can experiment and learn without fear of instant failure, and a mistake counter always keeps you aware of how many you have left. When it comes to choosing where to play, Shapedoku offers four difficulties so you can grow at your own pace: Easy is relaxed and perfect for learning the flow, Medium is a balanced challenge for comfortable regular play, Hard is for players who enjoy real deliberate logic, and Extreme is a serious test for confident, experienced solvers. There is also a fresh Daily Challenge every day, plus special modes like Speed and No Mistakes once the basics feel natural. Start on Easy, learn the rhythm of scanning and placing, and work upward. You can play right now in your browser at app.shapedoku.com, free and with no login.