What's tougher about Hard?
Hard puzzles start with very few sudoku digits and only one pre-revealed ship segment. You'll need to squeeze every clue from the row/column counts and the sudoku logic working together.
The good news: every Hard puzzle has exactly one solution and can be solved without guessing. If you feel stuck, the Check and Hint buttons are there to help.
Advanced deduction steps
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Zero and full rows/columns first
Count = 0 means no ships. Count = row/col length means all cells are ships. Resolve these before anything else.
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Partial elimination
If a row count is 2 and you've ruled out 7 cells as ship-free, the remaining 2 cells must both be ships.
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Use confirmed ships to cascade
Each confirmed ship removes cells from its row/col count. Update counts as you confirm ships.
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Cross-check with sudoku
A confirmed ship means those cells' digits are locked. That can solve neighbouring cells in the same row, column or box.
Preguntas frecuentes
Is Hard too tough for kids?
Hard is aimed at kids who've already played lots of Easy and Medium. If it feels overwhelming, go back to Medium for a few sessions first.
Can I solve Hard without guessing?
Yes — every puzzle has exactly one logical solution. If you're stuck, tap Hint to unlock one cell and keep going.
Prueba otros juegos de sudoku
Reglas distintas, el mismo tablero amable. Elige un puzzle hermano para tu próxima partida.