Classic Sudoku Expert

Expert Classic Sudoku is for players who treat the grid as a logic system: fish patterns, box-line interactions and locked candidates carry the solve. Givens are minimal, and guessing reliably leads astray. Every cell takes one of nine symbols: 123456789.

How to play Classic Sudoku

The board is a 9×9 grid divided into nine 3×3 boxes. Fill every empty cell so that each digit appears exactly once per row, column and box. Every puzzle we serve has a single valid solution.

• Each row contains the digits 1–9 exactly once.
• Each column contains the digits 1–9 exactly once.
• Each 3×3 box contains the digits 1–9 exactly once.
• Prefilled cells are fixed clues — everything else you deduce.

Expert Sudoku tips

At this depth you need patterns, not patience:

• The X-Wing. When a symbol’s candidates in two rows occupy the same two columns, that rectangle eliminates the symbol from every other cell in those columns.
• Quads, naked and hidden. Four cells sharing four candidates lock a unit exactly the way pairs do. Hidden quads show up often on expert boards once you stop expecting them to be obvious.
• Guess with discipline. If the grid truly stalls, pick a two-candidate cell, mark the branch and follow it to a contradiction or a breakthrough — then undo and take the other value if it breaks.

About Classic Sudoku

Classic Sudoku is the puzzle as it has been played for decades: a 9×9 grid, the digits 1–9, and one rule repeated three ways. It is still the most-played logic game in the world, and the level most solvers use to measure their speed.

More Classic Sudoku levels

Classic Sudoku Easy · Classic Sudoku Medium · Classic Sudoku Hard · Classic Sudoku Crazy

About Sudoku

Sudoku is a logic-based, combinatorial number-placement puzzle. In classic Sudoku, the goal is to fill a 9 x 9 grid with digits so that each column, each row, and each of the nine 3 x 3 subgrids that compose the grid contains all of the digits from 1 to 9. The puzzle setter provides a partially completed grid, which for a well-posed puzzle has a single solution.

About Sudokuing

Sudokuing(Sudoku'ing) is an online Sudoku gaming website that focuses on providing a user-friendly, variety of themed Sudoku puzzles for everyone to enjoy.