Changed digits can hide the same puzzle
Replace every 1 with a 7 and every 7 with a 1. Swap two rows inside a band. Rotate the finished grid. The board looks different, while the same clue pattern and deductions remain underneath.
Repeated structures become familiar. You may remember where the important cells sit even when every visible digit has changed. That reduces the value of starting a new puzzle.
One canonical ID covers every equivalent version
Sudoku Pilot converts each candidate into a canonical form. Digit relabeling, valid row and column permutations, band and stack swaps, rotations, reflections, and transposition all resolve to the same canonical ID.
The catalog rejects a candidate when that ID already exists. A transformed copy cannot increase the count of logically distinct puzzles.
Every catalog puzzle passes the solver checks
- The givens have exactly one solution.
- Sudoku Pilot can complete one full path with its supported logical techniques.
- The deterministic rating matches the catalog difficulty.
- Technique requirements describe methods the solver genuinely needs under its model.
- The canonical ID does not appear elsewhere in the catalog.
These guarantees apply to generated catalog puzzles. An imported puzzle is checked from the board you provide and does not come from this catalog.
Visual variety comes after puzzle selection
The app first selects a canonical puzzle you have not played on that device. It can then change the presentation without pretending the transformed board is another logical puzzle.
Played canonical IDs are stored on the device. The selection logic prefers an unseen identity before returning to one you have already solved.
Start a puzzle you have not already seen
Choose a difficulty and start a generated puzzle. The board comes from the certified catalog for that level, with its logical identity tracked separately from its appearance.