KOISCORE GAME GUIDE
Sudoku
Play Sudoku free in your browser on KOISCORE. No install required on mobile or desktop.
How to play
Select an empty cell
Tap the cell you want to fill.
Enter 1–9
Only digits missing from that row, column, and 3×3 box are allowed.
Complete the board
Fill every cell correctly to clear the puzzle.
Rules
Fill a 9×9 grid so each row, column, and 3×3 box contains 1–9 once. Use the given clues and logic—no guessing required.
Sudoku — how a number grid went global
The 9×9 sudoku we know was named and popularized in Japanese puzzle magazines before newspapers worldwide adopted it in the 2000s. It needs no arithmetic — only logic — which is why it became a commute habit, a brain-training cliché, and a daily app ritual.