All Sudoku Variants
9×9 + a hidden fleet · Constraint

Battleship Sudoku

A hybrid of Sudoku and Battleships: place the digits and a fleet of ships together, where ships never touch — even diagonally — and outside numbers count the ship segments in each row and column.

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An example Battleship Sudoku: a three-cell ship (navy) lies in row 3, which the outside clue 3 counts; ships never touch and their segments carry Sudoku digits.

Battleship Sudoku hides a fleet of ships inside a Sudoku grid. You solve both puzzles at once: fill the grid with 1–9 as usual, and place the ships so that no two touch — not even at a corner — while outside numbers tell you how many ship segments sit in each row and column.

The rule: two puzzles, one grid

Every row, column and region still needs 1–9. On top of that, a fleet of ships must fit the grid under standard Battleship rules: ships never touch each other, and the counts around the edge fix how many ship cells each line holds. The digits on the ship segments count toward the Sudoku, so the two layers constrain each other.

Solving strategy

  • Place the certain ships first. A line whose count matches its free space forces the ships immediately.
  • Use the no-touch rule. Around every placed ship, the surrounding cells must be sea — a powerful eliminator.
  • Let each layer feed the other. A fixed ship cell fixes a Sudoku digit, and a placed digit can rule a ship in or out.

Common mistakes

  • Letting ships touch. No two ships may share an edge or a corner.
  • Ignoring the edge counts. They pin the number of ship segments per row and column.
  • Solving only one layer. The Sudoku and the fleet must both be satisfied together.

Can I play it here?

Not yet — Battleship Sudoku isn't one of the puzzle types SudokuStreak generates for now. But you can learn its rules above, and there's plenty here to sink your teeth into meanwhile: