Shapedoku Smart Notes: Keep Your Pencil Marks Tidy

What Shapedoku smart notes actually do

Shapedoku smart notes are the pencil marks you leave inside an empty cell to record which shapes could still go there. In classic Sudoku you write these small candidates in a corner, then erase them by hand every time you place a number. Shapedoku does the erasing for you. When you commit a shape to a cell, Smart Notes Cleanup automatically removes that same shape from the notes in every cell that shares its row, its column, and its 3x3 box. The nine shapes stay the same as always: Orange Triangle, Blue Hexagon, Emerald Circle, Violet Crystal, Rose Heart, Golden Diamond, Teal Square, Pink Crescent Moon and Mint Lotus.

The point is trust. A pencil mark is only useful if it reflects the current state of the grid. Once you place a Rose Heart in a row, no other cell in that row can hold a Rose Heart, so any Heart note there is now noise. Shapedoku smart notes wipe that noise the instant it appears, which means the candidates you see are the candidates that are genuinely still possible.

Why stale notes cost you puzzles

Every wrong-looking option you leave on the board is a small tax on your attention. On Easy or Medium you can absorb that tax, but on Hard and Extreme the whole solve depends on spotting a cell with only one candidate left. If a dead shape is still glowing in three cells, you can stare past the exact naked single you needed. Cleaning notes by hand is also where mistakes creep in, because it is easy to forget one cell after a placement.

• A cell that should show one candidate no longer hides it behind shapes that are already used elsewhere.
• Hidden pairs and triples become far easier to see once the impossible shapes are gone.
• You spend your focus on logic instead of housekeeping.
• The board reads as calm rather than crowded, which fits the game's relaxing tone.

The auto-clean setting, and when to turn it off

Smart Notes Cleanup is controlled by an auto-clean setting, and it is on by default because that is the right choice for almost everyone. Leave it on and your Shapedoku smart notes maintain themselves for the entire puzzle. If you prefer full manual control, perhaps because you are practicing candidate tracking or working a specific solving technique, you can switch auto-clean off in settings and your notes will then stay exactly as you placed them until you change them yourself.

Cleanup is never destructive in a way you cannot recover. If a placement was a step too far, undo restores the previous notes state along with the move, so the shapes that were cleared come back. And even with auto-clean on, you always keep manual override: if you want a note back after it was removed, you can simply add it again. Cleanup is a convenience, not a lock.

A simple routine that works

1. Fill notes for the region you are working, or use them only where the logic gets tight.
2. Place a shape the moment you are certain, and let Smart Notes Cleanup prune the peers.
3. Re-scan the cleaned row, column and box for a new single that just appeared.
4. If you place by accident, undo to bring the old notes back, then continue.

Shapedoku smart notes turn note-keeping from a chore into a quiet assistant that keeps the grid honest. Try a Hard puzzle with auto-clean on and watch how often a placement instantly reveals the next one. You can play free in a browser at app.shapedoku.com or on Google Play, guest first with optional sign-in to sync.