Sudoku Proof vs Chesspy

Every move has a reason. Sudoku Proof is a clean, private Sudoku built for uninterrupted play and real learning. Start a puzzle instantly, finish it offline, and understand the logic when you want help. There are no ads, no account, no lives, and no subscription. PLAY A COMPLETE SUDOKU - Unlimited Easy, Medium, and Hard puzzles - A shared Daily Challenge, including Expert and Master days - Pencil notes with automatic cleanup - Unlimited undo and redo - Optional error checking and a timer you can hide - Automatic local saving after every move - Light and dark appearance on iPhone and iPad LEARN THE REASON Basic reveals help you finish without buying hint packs. Pro adds visual Logic Proofs that highlight the exact candidates, units, and eliminations behind the next step. Practice Singles, Locked Candidates, Pairs, Triples, X-Wing, Skyscraper, XY-Wing, and Swordfish. BRING YOUR OWN PUZZLE With Pro, type or paste an 81-cell puzzle, check whether it has one solution, see its difficulty, and solve it step by step. ONE PURCHASE, NO SUBSCRIPTION Pro includes every answer and all Pro features. One-time purchase. No subscription. Three sample answers per category are free to view again. Unlock Pro for all remaining answers. Existing answer-pack purchases can still be restored for their original difficulty. PRIVATE AND OFFLINE FIRST Your active game and history are stored locally. Private iCloud sync and Game Center are optional Apple services; either can be unavailable without stopping play or losing the local result.

Place chess pieces. Hit every number. Numbered squares are targets. Place chess pieces so each target is attacked by exactly its number — in the app, your pieces are called agents. A 0 is a safe square: nothing may attack it. Match every number and the next board is right there. Every board has exactly one solution, and you can reach it by logic alone — no guessing. Today’s Mission • Twenty boards in a row, growing from 3×3 to 6×6. • Three hearts. Placing or moving an agent so a number newly turns red costs one heart. Removing and undoing are always free. • Lose your last heart and you can see that board’s answer. • Everyone gets the same mission each day. Finish it to see your Top % today. • Sundays bring the S-Rank Mission: it starts at 4×4 and the last five boards are 7×7. Battles • Create a battle and get a six-digit code. Paste the link in a group chat and friends jump straight in. • Everyone plays the same five boards with three hearts. Most boards, then fewest hearts lost, then fastest time wins. • Up to 16 players, each joining as a chess piece: king, queen, rooks, bishops, knights and pawns. • A battle stays open for 7 days. Joining is free for anyone. The agents • The rook attacks along rows and columns, the bishop along diagonals — all the way to the edge, right past other agents. • From board 10 the knight joins in, jumping in an L. • No chess needed. A four-board tutorial shows you how on the board. More to play • Unlimited: opens after today’s mission. Endless boards that grow to 7×7 — two free runs a day. • Hints: stuck in Unlimited or a past mission? Get the reason for the next move, one step at a time. One free hint a day. • Past missions: anyone can play one past day for free. • Streaks, six achievements that unlock agent designs, and a result card to share. • Dark mode and a colour-blind palette. • English, Korean, Japanese, Traditional Chinese, French, German and Spanish. Pro (one-time purchase) • Unlimited, with no daily limit • Hints, with no daily limit • Create battles • Every past mission — fill a missed day to keep your streak • Every agent design and detailed stats • Pro never touches a daily score, and Today’s Mission has no hints. Everyone plays by the same rules. No ads. No account. Your records stay on your device; Top % and battles use only a random ID with no name.