Daily Expert Sudoku X
A fresh expert Sudoku X puzzle every visit — extreme technique on the diagonal grid.
Solve every day to build your streak — a free account saves your daily solves and climbs the leaderboard.
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All-TimeThe daily expert Sudoku X is the hardest diagonal tier we generate. With 20–22 givens and the diagonal constraint forcing the deepest deductions, almost every move comes from technique rather than scanning — swordfish on a diagonal, Unique Rectangle straddling both diagonals, XY-Wing chains that exploit the diagonal intersection at the centre cell. Sessions take real time; 30–60 minutes is normal, longer for the toughest grids. A fresh puzzle every visit means the daily expert Sudoku X is genuinely a daily trial. Sudoku247Online's diagonal-aware solver verifies every puzzle has a single legal solution before it ships.