Standard Sudoku

HOW TO PLAY

A place for every number

Fill each row, column and 3 × 3 box with 1–9, once each. Select a square, then type or tap a number. Arrow keys move; Space (or P) switches between pencil marks and number entry; hold Shift to temporarily use the other mode; Delete erases; Ctrl/⌘ Z undoes, Shift redoes. Matching digits, related squares and conflicting entries are highlighted. Toggle Available numbers to show every digit allowed by the current row, column and box. Your own pencil marks are preserved when you turn it off.

Easy uses naked singles; Medium also needs hidden singles; Hard needs locked candidates or naked pairs; from 3 November 2026, each Hard grid requires at least four placements requiring advanced techniques. Hints explain the next logical placement. Hints carry no penalty: your score is elapsed active time only. The timer begins with your first entry or hint and pauses when the window loses focus or the tab is hidden. Choose Resume to continue. Replays keep every completed time.

The same three puzzles are available to everyone on each local calendar date. Progress stays in this browser. Stars require strictly less than 3:00, 5:00 or 10:00. Chart columns stop at those targets; hover or focus for actual times.