Solving Sudoku: Techniques from Beginner to Expert

Sudoku is not a math game — it's a game of pure logic. On GameJoc you play a 9x9 board with notes, undo, up to 3 hints, a timer and a 3-mistake limit. Scoring rewards difficulty and speed, but penalizes hints and errors.

Technique 1: Scanning

The most basic technique. For each number (1-9), scan rows and columns looking for where it CANNOT go. If in a 3x3 box only one cell remains possible for a number, that's where it goes.

Technique 2: Naked Pairs

If two cells in the same row/column/box can only contain the same two numbers (e.g., 3 and 7), you can eliminate those numbers from all other cells in that row/column/box. Even though you don't know which goes where, you know 3 and 7 are "reserved."

Technique 3: Hidden Single

Sometimes a cell seems to have multiple candidates, but if you look at the entire row, column, or box, you discover it's the ONLY cell where a specific number can go. That number must go there.

Technique 4: X-Wing (Advanced)

If a candidate number appears in exactly the same two columns across two different rows, you can eliminate that candidate from the rest of those columns. It's like a "cross-block."

General Tip

Use pencil marks (or the game's notes feature). Mark all possible candidates in each empty cell. This transforms Sudoku from an impossible mental exercise to a methodical elimination process.