Pencil Notes

Pencil notes (also called pencil marks or candidates) are small digits written in cells to track which values are still possible. They're an essential tool for solving Sudoku puzzles beyond the easiest levels.

Automatic Note Management

Lazy Sudoku maintains pencil notes automatically:

This means you can focus on solving rather than bookkeeping.

Selecting Cells

To edit notes, first select one or more cells:

Action Result
Tap a cell Select that cell
Double-tap a cell Select and enter notes mode
Swipe across cells Select multiple cells
Tap while selecting Add/remove cells from selection
Stylus drag Select cells along the stroke path
Stylus lasso Select all cells enclosed by the loop

Once multi-select is active, swiping toggles cells — swiping over an already-selected cell deselects it. This XOR behaviour applies equally to finger swipes and stylus drags.

Selection lifecycle: after editing notes within a selection, the next tap, swipe, or stylus drag starts a new selection. This lets you edit multiple candidates in the same selection before moving on. To clear the selection entirely, exit notes mode.

With multiple cells selected, you can edit notes in all of them simultaneously.

Naked Set Detection

When your selected cells form a naked set — N cells with exactly N shared candidates in the same unit — the status bar highlights the set information in blue. Tap the status bar to expand the selection to all peer cells in the shared unit, i.e. the cells where those candidates can be eliminated. This lets you quickly select peers and exclude candidates in bulk.

Stylus Selection

When using a stylus, you have two additional selection methods:

Stylus strokes edit the selection the same way finger swipes do — there is no special clearing behaviour. See Stylus Settings for configuration options.

Multi-Finger Gestures

Tap the grid with multiple fingers to trigger configurable actions:

Fingers must remain still; movement cancels the gesture. You can change these assignments in Multi-finger settings.

Note Editing Modes

Tap the notes button to cycle through editing modes, or double-tap a cell to enter the last used mode.

Exclude Mode

Use exclude mode to mark candidates you've determined are impossible.

Digit pad behaviour: current → excluded → normal

Excluded candidates appear with a strikethrough and are dimmed. This helps you track your deductions without removing notes entirely.

Highlight Mode

Use highlight mode to mark candidates you want to focus on.

Digit pad behaviour: current → highlighted → normal

Highlighted candidates appear in a distinct colour, making patterns easier to spot.

Auto-highlighting and manual highlighting are independent — the engine's auto-highlights use a separate visual style and never overwrite your highlights. Both can be active simultaneously.

Manual Mode

Use manual mode for plain on/off candidate notes — no highlights, no exclusions in the loop.

Digit pad behaviour: none → normal, anything else → none

The first tap on a digit adds it as a normal candidate; the next tap removes it. Use Highlight or Exclude mode when you actually want those states — manual mode stays focused on adding and removing candidates as quickly as possible.

Power Notes

Power Notes lets you apply note changes automatically just by selecting cells — no need to tap the digit pad after each selection.

How It Works

  1. Focus a single digit using Digit Focus (long-tap a digit button)
  2. Activate Power Notes by long-tapping the corresponding note mode button (Exclude, Highlight, or Manual) — a glow indicator confirms it's active
  3. Select cells by tapping or swiping — the focused digit's note is toggled automatically in every selected cell

Power Notes works with all three note modes:

Mode Button Effect
Power Exclude Long-tap Exclude Auto-toggles exclusion on cell selection
Power Highlight Long-tap Highlight Auto-toggles highlight on cell selection
Power Manual Long-tap Manual Auto-toggles note state on cell selection

Tap, Swipe, and Double-Tap

Retain Selection

By default, cells stay selected after Power Notes applies, so you can see which cells were affected and continue working.

If you prefer a fire-and-forget workflow, turn off Retain Selection in Power Notes settings. With this off, the selection clears immediately after Power Notes applies — keeping the grid clean between each action.

Tips

  1. Batch exclusions — Focus a digit, activate Power Exclude, then swipe across a row or column to exclude that digit from all swiped cells at once
  2. Quick highlighting — Use Power Highlight to rapidly mark cells of interest without extra taps
  3. Combine with Digit Focus — Power Notes only activates when exactly one digit is focused, so switching focus digits changes what gets applied
  4. Deactivate — Long-tap the mode button again to turn Power Notes off, or switch to value mode

Each Power Notes mode (Exclude, Highlight, Manual) can be toggled independently in Input settings.

Stylus Note Editing

With a stylus, you can edit candidates using natural gestures directly on the grid:

Bulk editing: select multiple cells first, then perform a stylus gesture — the action applies to the same candidate across all selected cells. For example, select a row of cells, then strikethrough candidate 5 to exclude it from all of them.

See Stylus Settings for gesture configuration.

Tips

  1. Double-tap for speed — Double-tap a cell to quickly enter notes mode
  2. Multi-select for bulk edits — Swipe to select cells and edit notes in all at once
  3. Lasso and bulk edit — Use the stylus lasso to select an irregular group, then exclude candidates in one gesture
  4. Use exclusions liberally — Marking impossible candidates helps track your logic
  5. Multi-finger shortcuts — Use 2-finger tap to undo and 4-finger tap to toggle notes mode without reaching for buttons
  6. Let the engine help — Automatic note management saves time on routine eliminations

Related Features