Play free daily Sudoku and 16x16 Hexadoku puzzles with unique solutions, smart pencil notes, 3-mistake limit, and monthly trophy awards.
Fundamental rules of 9x9 and 16x16 Hexadoku puzzles and logical deduction techniques.
Fill the 9x9 grid so every row, column, and 3x3 box contains digits 1 through 9 exactly once with zero duplicates. You are allowed up to 3 mistakes before Game Over.
A grander puzzle consisting of a 16x16 grid with sixteen 4x4 subgrids. Each row, column, and 4x4 box must contain the digits 1 to 9 and letters A to G (16 distinct symbols).
Scan adjacent rows and columns for a specific number to eliminate rows and columns within a target box. This pinpoint technique reveals where a number must reside.
Each calendar day features a unique UTC seeded puzzle. Solve 3 days for Bronze, 10 days for Silver, 20 days for Gold, and 28+ days for the Diamond Grandmaster Crown!
Learn strategies, rules, and tips to level up your gameplay in Sudoku.
Master essential Sudoku solving techniques from cross-hatching and sole candidates to candidate pencil notes with clear walkthroughs.
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Key answers regarding rules, controls, and features for Sudoku.
Standard challenge mode permits a maximum of 3 mistakes. When an incorrect digit is entered, a strike is recorded. Reaching 3 mistakes concludes the game, with options to take a Second Chance, restart, or begin a new puzzle.
16x16 Sudoku (Hexadoku) is divided into 16 subgrids of 4x4. The symbols used are digits 1 through 9 and letters A through G (totaling 16 unique symbols). Each row, column, and 4x4 box must contain all 16 symbols without repetition.
Every day has a unique puzzle generated deterministically from its UTC date seed. You can open the Daily Calendar to play past days and track your monthly solves. Completing 3, 10, 20, or 28 days in a month unlocks Bronze, Silver, Gold, and Diamond monthly trophies.
Pencil notes allow you to jot down candidate possibilities in empty cells, updating automatically as numbers are placed. Hints highlight logical moves step-by-step with zero penalties on your solve record.
