ShroomdokuHow to play
Shroomdoku.
Coming soon to iPhone. Preview the four rules before the App Store launch.
The four rules of Shroomdoku
- Every row contains exactly one mushroom.
- Every column contains exactly one mushroom.
- Every colored region contains exactly one mushroom.
- Mushrooms cannot touch, including diagonally.
Unlike Sudoku, there are no numbers to enter. Most squares stay without mushrooms. Regions are irregular connected groups, rather than fixed boxes. A 6×6 board needs six mushrooms; a 10×10 board needs ten.
The diagonal rule applies to touching corners, not an entire diagonal. Mushrooms farther apart on the same diagonal are allowed.
Solve your first mushroom puzzle
When the app launches, choose Learn to play on Home. The guided 6×6 practice board is separate from your saved game, and practice mistakes spend no hearts or hints.
Teaching diagram from the actual practice puzzle. The game is played in the iPhone app.
- Find the tiny region. The top-left colored region has only one square: row 1, column 1. Every region needs a mushroom, so this must be its home.
- Double tap to place Flora. Then cross out the other five squares in row 1 and the other five in column 1.
- Remember the corners. Cross out row 2, column 2 because it touches Flora diagonally.
- Look again. Find another row, column, or region with just one possible position.
Tap, mark, and place: the controls
| In the app | What happens |
|---|---|
| Tap an empty square | Add an X note. |
| Tap an X | Remove the note. |
| Double tap a square | Attempt a mushroom. |
| Tap a placed mushroom | Remove it. |
| Drag from an empty square | Mark a sweep of Xs. |
| Drag from an X | Erase a sweep of notes. |
| Undo | Reverse the last note edit, or a whole sweep. |
Notes are manual and never cost hearts. Placing a mushroom does not cross out other squares automatically. Undo applies to notes; it does not reverse mushroom attempts, restore hearts, or refund assistance.
Solving strategies by difficulty
Easy · Direct deductions
Look for a row, column, or region with only one legal square. A mushroom rules out its row, column, region, and touching neighbors. If all possibilities for one color lie in a single row or column, that line is reserved for that color.
Medium · Locked groups
If two colors can place their mushrooms only in the same two rows, those rows are reserved for them. Other colors must go elsewhere. This also works with columns and with larger restricted groups.
Hard · What-if proofs
Imagine a mushroom in a candidate square and follow the deductions. If a row, column, or region ends up with nowhere for its mushroom, the original assumption cannot be right.
How hints and free mushrooms work
Every new puzzle includes free nudges, three distinct explanations, and one separate free mushroom. Rereading an explanation or applying it costs no additional allowance. Restart keeps the assistance you have remaining; starting a new puzzle resets it.
Wrong mushroom attempts cost one of three hearts, even if they do not visibly touch another mushroom. The app checks the puzzle’s unique solution. Experimenting with X notes is always safe.
Contact Shroomdoku support ↗