Kaizen (改善) means continuous improvement through small, steady steps. This is a Sudoku app built around that idea: after every game, one focused insight — a missed technique, a hesitation pattern, a personal best — so you actually get better, not just occupied.
The learning engine tracks hesitation, mistakes, and missed techniques as you play, then surfaces exactly one actionable insight after each game — never a wall of stats.
Puzzles are rated by which solving technique they actually require — naked singles up through box-line reduction, X-Wings, and Swordfish — not just clue count. Progress is tracked per technique.
A shared puzzle each week, ranked against friends on a leaderboard. Using a hint disqualifies that entry, so the board reflects real solves.
No sign-up, no email, no ads or tracking SDKs. Play is local-first and syncs when you're online. Delete all your data any time from Settings.
Questions or help: support.kaizensudoku@matteraps.com