Puzzle Editor

The puzzle editor lets you create custom Sudoku puzzles from scratch, edit saved puzzles, and review grids imported via OCR or text input. It provides real-time validation, difficulty analysis, and solution counting — everything you need to craft and refine puzzles before playing them.

Getting Started

You can open the editor in several ways:

• New puzzle — tap "Create" from the puzzle list to start with an empty grid
• Edit saved puzzle — tap the edit button on a saved puzzle to modify it
• OCR review — after scanning a puzzle with the camera, the editor opens in review mode so you can verify and correct the recognised digits
• Text input — paste a puzzle string and the editor validates and loads it

Placing Digits

With a cell selected, tap a digit on the keypad to place it. Tapping the same digit again cycles through states:

Givens are the fixed clues that define the puzzle. User values are useful when setting up partially-solved states or testing placements.

To clear a cell directly, use the Clear button, or press 0, Delete, or Backspace.

Notes Mode

Tap the Notes button on the keypad (or press N) to toggle notes mode. In notes mode, tapping a digit toggles that candidate on or off in the selected cell.

Notes are optional in the editor — they're useful when preparing partially-solved puzzle states or importing puzzles in S9B format that include candidate information.

Stylus Input

The editor supports Apple Pencil and other stylus devices for natural digit entry.

Drawing Digits

Draw a digit directly on a cell to place it. The editor uses pressure sensitivity to determine whether to place a given or a note:

Stroke colour changes to reflect the mode — value strokes and note strokes use distinct colours from your theme.

Gestures

Error Feedback

• Red flash — the drawn digit conflicts with existing values in the same row, column, or box
• Orange flash — the stroke wasn't recognised as a valid digit or gesture

Status Banner

The status banner at the top of the editor shows real-time information about your puzzle:

When conflicts are present, the affected cells are highlighted in red on the grid.

Analysis

Automatic Analysis

The editor automatically runs a quick analysis after each change:

• Conflict detection — flags cells that violate Sudoku rules
• Solution counting — checks whether the puzzle has zero, one, or multiple solutions
• Difficulty estimate — when exactly one solution exists, shows a difficulty score and category

Detailed Analysis

Tap the Analyse button on the keypad to run a full technique-based analysis. This opens a banner showing:

• Overall difficulty score and category
• Number of solving steps
• Each technique used, with counts

Detailed analysis is only available when the puzzle has exactly one solution.

Counting All Solutions

When the quick check finds multiple solutions, tap the Count button on the status banner to count all solutions (up to 100,000). The result includes elapsed time.

Show Solution

Tap the Solution button on the keypad to toggle a solution overlay. This shows what the completed grid looks like, helping you verify that the puzzle solves to the intended state.

The solution overlay is only available when the puzzle has exactly one solution.

Saving Puzzles

First Save

Tap Save to name and store your puzzle. A default name is suggested — you can accept it or type your own.

Updating

After the first save, tapping Save silently updates the existing puzzle. The save icon shows an accent colour when there are unsaved changes.

Save As

Use Save As (available after the initial save) to store a copy under a new name. The editor suggests an incremented name — e.g., "My Puzzle" becomes "My Puzzle 2".

Puzzles with conflicts cannot be saved.

Sharing

Choose Share from the overflow menu to share your puzzle as a URL via the system share sheet. Recipients can open the link to load the puzzle directly.

Clear & Generate

From the overflow menu:

• Clear Grid — removes all digits, resetting to an empty grid
• Generate — fills the grid with a random complete solution (useful as a starting point — remove clues to create your puzzle)

OCR Review Mode

When you enter the editor after scanning a puzzle with the camera, the original image is displayed behind the grid so you can compare the recognised digits against the source.

Two additional buttons appear in the navigation bar:

• Invert Colours — inverts the background image for better contrast
• Hide Values — hides cell values so you can see the background image clearly

This makes it easy to spot and correct any OCR misreads before saving.

Navigation Bar

The navigation bar provides quick access to editor actions:

The overflow menu (⋯) contains: Clear Grid, Generate, Share, Send Feedback, and Settings.

Keyboard Shortcuts

On devices with a hardware keyboard:

Layout

The editor uses the same responsive layout as the game screen:

• Portrait — grid on top, keypad below
• Landscape — grid and keypad side by side
• Left-handed mode — mirrors the layout so the keypad is on the left

Tips

1. Start from a generated grid — use Generate to create a complete grid, then remove clues to design your puzzle
2. Watch the status banner — it tells you immediately if your puzzle is solvable and unique
3. Use Analyse for difficulty — check which techniques are needed to solve your puzzle
4. Save often — the accent on the save icon reminds you when there are unsaved changes
5. Use OCR review — after scanning, toggle Hide Values to compare against the original image
6. Try stylus pressure — with a stylus, light strokes place notes and firm strokes place givens

Related Features

• Pencil Notes — How candidates work in the game
• Using the Digit Pad — Digit entry and swipe gestures