Logic & Sudoku Games
Number-sequence Practice, verified deduction grids, unique-solution Sudoku, no-guess mine logic, Four in a Row and American Checkers strategy.
Choose a game
Choose a Quick/Deep number-sequence round, a 60/120-second Pattern Sprint, a multi-clue deduction grid, or a full 9×9 Sudoku solve.
Hitori
Shade duplicate numbers on 4×4 through 7×7 verified boards while black cells stay separated and the remaining white area stays connected.
Open Hitori →V0.98 · GUIDEHitori Online
Learn duplicate-pair, no-touch and connectivity deductions with explicit Shade and Keep tools.
Explore →V0.98 · DAILYDaily Hitori
One date-stable verified number-elimination board with local specialist history.
Play daily →V0.98 · INEQUALITY LOGICFutoshiki
Fill Latin-square grids from 4×4 through 7×7 while satisfying horizontal and vertical inequality clues on independently verified boards.
Open Futoshiki →V0.98 · GUIDEFutoshiki Online
Learn row/column uniqueness, inequality chains, candidate ranges and the clean-versus-assisted record contract.
Explore →V0.98 · DAILYDaily Futoshiki
One date-stable verified inequality puzzle with browser-local history and a specialist streak separate from Today’s 6.
Play daily →V0.96 · STRATEGYShogi
Japanese Chess with captured-piece drops, promotion, nifu and king-safety rules against local AI.
Open Shogi →V0.96 · GUIDEShogi Game
Learn the reserve-piece, promotion and drop rules behind the full browser game.
Explore →V0.96 · DAILYDaily Shogi
One date-stable Japanese Chess session with separate local history and streak.
Play daily →V0.96 · STRATEGYXiangqi
Chinese Chess with palace, river, cannon-screen, horse-leg and flying-general rules against local AI.
Open Xiangqi →V0.96 · GUIDEXiangqi Game
Learn the distinct movement and ending rules behind the full browser game.
Explore →V0.96 · DAILYDaily Xiangqi
One date-stable Chinese Chess session with separate local history and streak.
Play daily →PUZZLEMahjong Solitaire
Match free tile pairs across guaranteed-solvable layered Pyramid, Terraces and Fortress deals.
Play →FOCUSEDMahjong Solitaire Guide
Learn the free-tile rule, solvable-deal guarantee and clean-versus-assisted scoring.
Explore →DAILYDaily Mahjong Solitaire
Play one deterministic solvable layered deal per date with a separate local streak.
Play daily →V0.68 · STRATEGYCheckers
American 8×8 play with mandatory captures, multi-jumps, four browser-local AI levels and 120 validated tactical positions.
Open Checkers →V0.183 · EXPLAINABLE SUM LOGICKiller Sudoku
Five verified Practice tiers—including zero-given Pure—with exact cage combinations, multi-cell auto-sum, Rule-of-45 scanning and an explainable next-step coach.
Open Killer Sudoku →V0.58 · NO-GUESSMinesweeper
Clear 9×9, 16×16 or 30×16 minefields accepted only after the deduction solver proves a no-guess path from the protected opening.
Open Minesweeper →PLAY NOWPattern Logic
240 Practice sequences across eight rule families, three difficulty bands and Quick, Deep or Sprint play.
Open Practice →PLAY NOWLogic Grid
Interactive deduction with verified unique solutions.
Open Practice →PLAY NOWSudoku
A uniquely solvable 9×9 puzzle with notes and coaching.
Open Practice →V0.78 · LEARNSudoku Technique Lab
Practice 40 deterministic candidate-pattern drills across Singles, Locked Candidate, Pairs, Naked Triple and X-Wing.
Train techniques →V0.57 PICTURE LOGICNonogram
Reveal a hidden pattern from row and column clues using 120 solver-verified 5×5, 10×10 and 15×15 sources.
Open Nonogram →Choose a game
Choose a Quick/Deep number-sequence round, a 60/120-second Pattern Sprint, a multi-clue deduction grid, or a full 9×9 Sudoku solve.
Skyscrapers
Fill verified 4×4 through 6×6 Latin-square cities while edge clues count how many buildings are visible from each viewpoint.
Open Skyscrapers →V0.99 · GUIDESkyscrapers Puzzle Online
Learn visibility counts, opposite-edge deductions, Pencil Notes and the unique-solution release contract.
Explore →V0.99 · DAILYDaily Skyscrapers
One date-stable verified skyline with browser-local history and a specialist streak separate from Today’s 6.
Play daily →V0.98 · INEQUALITY LOGICFutoshiki
Fill Latin-square grids from 4×4 through 7×7 while satisfying horizontal and vertical inequality clues on independently verified boards.
Open Futoshiki →V0.98 · GUIDEFutoshiki Online
Learn row/column uniqueness, inequality chains, candidate ranges and the clean-versus-assisted record contract.
Explore →V0.98 · DAILYDaily Futoshiki
One date-stable verified inequality puzzle with browser-local history and a specialist streak separate from Today’s 6.
Play daily →V0.96 · STRATEGYShogi
Japanese Chess with captured-piece drops, promotion, nifu and king-safety rules against local AI.
Open Shogi →V0.96 · GUIDEShogi Game
Learn the reserve-piece, promotion and drop rules behind the full browser game.
Explore →V0.96 · DAILYDaily Shogi
One date-stable Japanese Chess session with separate local history and streak.
Play daily →V0.96 · STRATEGYXiangqi
Chinese Chess with palace, river, cannon-screen, horse-leg and flying-general rules against local AI.
Open Xiangqi →V0.96 · GUIDEXiangqi Game
Learn the distinct movement and ending rules behind the full browser game.
Explore →V0.96 · DAILYDaily Xiangqi
One date-stable Chinese Chess session with separate local history and streak.
Play daily →PUZZLEMahjong Solitaire
Match free tile pairs across guaranteed-solvable layered Pyramid, Terraces and Fortress deals.
Play →FOCUSEDMahjong Solitaire Guide
Learn the free-tile rule, solvable-deal guarantee and clean-versus-assisted scoring.
Explore →DAILYDaily Mahjong Solitaire
Play one deterministic solvable layered deal per date with a separate local streak.
Play daily →V0.68 · STRATEGYCheckers
American 8×8 play with mandatory captures, multi-jumps, four browser-local AI levels and 120 validated tactical positions.
Open Checkers →V0.183 · EXPLAINABLE SUM LOGICKiller Sudoku
Five verified Practice tiers—including zero-given Pure—with exact cage combinations, multi-cell auto-sum, Rule-of-45 scanning and an explainable next-step coach.
Open Killer Sudoku →V0.58 · NO-GUESSMinesweeper
Clear 9×9, 16×16 or 30×16 minefields accepted only after the deduction solver proves a no-guess path from the protected opening.
Open Minesweeper →PLAY NOWPattern Logic
240 Practice sequences across eight rule families, three difficulty bands and Quick, Deep or Sprint play.
Open Practice →PLAY NOWLogic Grid
Interactive deduction with verified unique solutions.
Open Practice →PLAY NOWSudoku
A uniquely solvable 9×9 puzzle with notes and coaching.
Open Practice →V0.78 · LEARNSudoku Technique Lab
Practice 40 deterministic candidate-pattern drills across Singles, Locked Candidate, Pairs, Naked Triple and X-Wing.
Train techniques →V0.57 PICTURE LOGICNonogram
Reveal a hidden pattern from row and column clues using 120 solver-verified 5×5, 10×10 and 15×15 sources.
Open Nonogram →Focused challenges
Evergreen entry points connect a specific search intent to the real Practice mode instead of duplicating the game.
Checkers Online
Play full American checkers versus local AI or a friend, then drill validated capture and safety tactics.
V0.68 · DAILYDaily Checkers Tactic
One date-stable validated tactic with a separate browser-local streak.
V0.60 · KILLER SUDOKUKiller Sudoku Online
Play the full cage-sum Sudoku specialist with combinations and local autosave.
V0.60 · DAILY KILLERDaily Killer Sudoku
One reproducible cage Sudoku per local day with its own streak.
V0.58 · CLASSIC LOGICMinesweeper Online
Play classic Beginner, Intermediate and Expert boards with chording, autosave and local 3BV metrics.
V0.58 · DEDUCTION ONLYNo-Guess Minesweeper
Use a protected opening and boards rejected unless the built-in verifier can finish without a guess.
EVERGREEN CHALLENGELogic Grid Puzzles
Solve interactive 3×3 and 4×4 deduction-grid puzzles with verified unique solutions.
EVERGREEN CHALLENGEPattern & Sequence Quiz
Practice 240 number-sequence fixtures with explanations, three difficulty bands and 60/120-second Sprints.
EVERGREEN CHALLENGESudoku Practice
Play a uniquely solvable 9×9 Sudoku with Easy, Medium, Hard and Expert practice pools from 160 verified grids plus optional logical coaching.
V0.147 · TECHNIQUE ACADEMYSudoku Techniques
Practice 72 verified candidate states across nine techniques, from Singles and locked candidates through Swordfish and Skyscraper.
V0.57 NONOGRAMNonogram Puzzle Online
Play solver-verified picture logic with Fill/X drag, Undo/Redo, Hint, autosave and clean PBs.
V0.57 DAILYDaily Nonogram
Three date-stable logic-only boards per day with a separate specialist streak.
Daily for habit
Today's 6 keeps the main routine short: one rotating game from each pillar and a single 6,000-point daily score.
Practice for depth
Practice can be repeated without changing the Daily Score, so search visitors can immediately play the exact skill they came for.
Related discovery
Every hub links into neighboring challenges so a visitor who finishes one game has a natural next task instead of a dead end.
Daily and printable deduction
Use the expanded verified library as a repeatable daily ritual or a clean paper worksheet.
Daily, fresh and printable Sudoku
Use the expanded 160-grid verified bank as a date-stable daily puzzle, unlimited fresh Practice or a clean paper grid.
Choose a Sudoku or Deduction difficulty
Jump directly into a verified Practice pool at the level you want.
Easy Sudoku Online
Play free easy Sudoku online with a verified unique-solution 9×9 puzzle and optional Notes, Auto Notes and Technique Coach.
DIFFICULTY PRACTICEMedium Sudoku Online
Play free medium Sudoku online with a verified unique-solution 9×9 puzzle and optional Notes, Auto Notes and Technique Coach.
DIFFICULTY PRACTICEHard Sudoku Online
Play free hard Sudoku online with a verified unique-solution 9×9 puzzle and optional Notes, Auto Notes and Technique Coach.
V0.28 DIFFICULTY PRACTICEExpert Sudoku Online
Play the new 24-clue Expert pool with the same Notes and coaching tools.
DIFFICULTY PRACTICEEasy Logic Grid Puzzles
Solve free easy logic grid puzzles online with interactive deduction cells and independently verified unique solutions.
DIFFICULTY PRACTICEStandard Logic Grid Puzzles
Solve free standard logic grid puzzles online with interactive deduction cells and independently verified unique solutions.
DIFFICULTY PRACTICEHard Logic Grid Puzzles
Solve free hard logic grid puzzles online with interactive deduction cells and independently verified unique solutions.
DIFFICULTY PRACTICEExpert Logic Grid Puzzles
Solve free expert logic grid puzzles online with interactive deduction cells and independently verified unique solutions.
Reversi strategy
Classic 8×8 mobility, corners and exact endgame counting.
Reversi endgame training
Play full games, then calculate exact late endings from the same local rules engine.
Code Breaker logic
Turn exact-position and right-symbol feedback into constraints, then verify your reasoning with an optional exact candidate engine.
Code-breaking challenges
Unlimited deduction practice or one same-for-the-date Standard code with a separate streak.
Spider Solitaire strategy
Expose hidden cards, consolidate same-suit descending runs and time five stock rows across 1-suit, 2-suit and 4-suit play.
FreeCell strategy
All 52 cards are visible, so the puzzle is about workspace, sequencing and planning rather than hidden luck.
Mancala strategy
Count sowing paths, chain store landings and compare captures in the common six-pit Kalah ruleset.
Dominoes endpoint strategy
Read public pip counts, manage hidden information and calculate fully known Block endings.
Klondike Solitaire
Turn 1 or Turn 3 classic Klondike with Daily Solitaire, autosave, Hint and local clean records.
Play →Hearts card strategy
Track suits, duck dangerous tricks and manage the Queen of Spades against browser-local computer players that cannot read hidden opponent hands.
Spades partnership strategy
Bid a team contract, manage trump, protect or attack Nil, and control bags against fair browser-local computer players.
Backgammon race & contact strategy
Use complete dice sequences, bar priority, blocking, hits and bearing off against a fair browser-local computer.
Chess strategy
Play a complete game with legal check, castling, en passant, promotion and draw detection against browser-local AI.
Go board strategy
Practice liberties, captures, connection and territory with a compact complete-rules Go specialist.
Gin Rummy draw-and-discard strategy
Build sets and suited runs, track deadwood, and decide when to knock against a fair browser-local opponent.
Cribbage counting & pegging strategy
Choose two cards for the crib, manage the running count to 31, then count fifteens, pairs, runs, flushes and nobs exactly.
Euchre partnership & trump strategy
Call trump, learn the right and left bowers, decide when to go alone and take three of five tricks with your partner.
Block Puzzle spatial planning
Place fixed-orientation shapes on an 8×8 board, clear complete rows and columns, and preserve flexible landing zones for the whole three-piece tray.
Block Puzzle Online
Play deterministic 8×8 Practice runs or a 50-Piece Challenge with three-piece trays, transparent clears, Hint, Undo and autosave.
V0.96 · DAILY BLOCK PUZZLEDaily Block Puzzle
One date-stable piece stream with local history and a specialist streak separate from Today’s 6.
Pyramid Solitaire pair-to-13 strategy
Clear a seven-row card pyramid by pairing exposed ranks to thirteen, timing the stock carefully and deciding which removals unlock the strongest follow-up cards.
Pyramid Solitaire Online
Play deterministic one-pass or three-pass Practice with pair-to-13 rules, King removal, Hint, Undo and autosave.
V0.96 · DAILY PYRAMIDDaily Pyramid Solitaire
One date-stable one-pass deal with browser-local history and a specialist streak separate from Today’s 6.
Yacht Dice
Manage five dice and thirteen one-use score rows with deterministic Practice, Daily play and a fair browser-local AI.
Open Yacht Dice →Binary Puzzle
Verified 6×6–12×12 Takuzu with balanced 0/1 counts, no triples, unique completed lines, Daily play and local autosave.
Open Binary Puzzle →Slitherlink
Trace one continuous closed loop on verified 5×5–7×7 dot grids. Number clues count surrounding loop edges while every used dot must have degree two.
Light Up · Akari
Place bulbs to illuminate every white corridor, keep bulbs out of one another’s sight, and satisfy numbered black-wall clues on verified 5×5–7×7 boards.
Open Light Up →Hashi · Bridges
Connect numbered islands with one or two straight bridges, avoid crossings, satisfy every island degree and finish with one connected network on verified 7×7–9×9 boards.
Star Battle · Two Not Touch
Place one star in every row, column and connected region while the no-touch rule eliminates all eight neighboring cells.
Box-pushing planning
Sokoban adds irreversible push planning with exact minimum-push verification.
Peg-jump elimination
Peg Solitaire adds one-player reachability planning across Triangle, English and European topologies, with a solver-proved Classic English center finish.
Tents & Trees
A one-to-one matching puzzle where tree adjacency, edge counts and the eight-neighbor no-touch rule interact.
Nurikabe · Islands & Walls
A pure deduction grid where exact islands, Sea connectivity and the no-2×2 rule constrain one another.
Shikaku · rectangle partition logic
Factor clue areas, eliminate blocked rectangle shapes and cover the full grid on independently unique 6×6, 8×8 and 10×10 boards.
Thermometers · count-constrained paths
Fill each path continuously from bulb to tip and use crossing row/column totals to force exact levels on straight and curved thermometers.
Number Path · sequential path logic
Bridge fixed number anchors with one continuous orthogonal sequence, using distance, parity and candidate pressure to resolve independently unique boards.
Pipes · rotate one connected network
Use boundaries, pipe degree, reciprocal edges and whole-network connectivity to orient every tile, with locks and live remaining-orientation feedback.
Fillomino · region capacity logic
Use exact region sizes, equal-number separation and candidate pressure on independently unique local puzzles.
Maze · verified perfect labyrinths
Navigate unique-route mazes with shortest-path efficiency, backtrack and dead-end telemetry.
Dominosa · exact-cover domino pairs
Pair every cell once while using every unordered number pair exactly once, with X marks, a live pair ledger and independently verified unique solutions.