Sudoku-ru

Sudoku, mastered. Sudoku-ru is the sudoku app you'll actually keep on your home screen. A premium board, a daily challenge that grows your streak, four game modes, and a hint engine that teaches sudoku — not one that just hands you the answer. FOUR WAYS TO PLAY Classic 9×9 — the original Mini 6×6 — perfect for a quick run Sudoku X — both diagonals must also contain 1–9 Killer Sudoku — cages with sums replace given clues FIVE DIFFICULTY TIERS Easy, Medium, Hard, Expert, Evil — every puzzle is uniqueness-verified, so there is always exactly one solution. DAILY CHALLENGE A fresh puzzle every day, seeded so it's the same for everyone. Build your streak, hit your best time, and watch the calendar fill up. A HINT ENGINE THAT TEACHES The hint chain detects Naked Singles, Hidden Singles, Naked Pairs, Pointing Pairs, and X-Wing — and names the technique so you actually learn it, not just the next digit. DESIGNED TO RESPECT YOUR TIME Pencil notes with auto-clear, unlimited undo and redo, peer and error highlighting, mistake limit with a one-time Watch-Ad revive, and iCloud sync so your streak and stats follow you to every device. STATS AND ACHIEVEMENTS Win-rate chart, streak rings, per-difficulty time breakdowns, and a trophy case you unlock as you play. SUDOKU-RU PREMIUM — one-time purchase Remove all ads, unlock every theme, and keep your hint tokens forever. Hint Packs (3, 20, or 100 tokens) are also available as one-time consumables. Sudoku-ru works fully offline, syncs across devices via iCloud, and has no subscriptions.