Battleship10×10 grid

Goal of the game

Sink the whole enemy fleet before your opponent sinks yours.

Each player places their ships on their own 10 × 10 grid, hidden from the other, then you take turns firing by calling out a cell.

The fleet

• Aircraft carrier — 5 cells.
• Battleship — 4 cells.
• Destroyer and submarine — 3 cells each.
• Patrol boat — 2 cells.
• Seventeen cells taken out of a hundred: the fleet covers 17% of the grid, which is why the first shots miss so often.

Placing your fleet

• Ships are placed horizontally or vertically, never diagonally, without overlapping.
• Avoid the edges. It is everyone’s reflex, so it is the first place your opponent looks.
• Do not put your ships side by side. A hit reveals an area: if two ships touch, sinking the first gives away the second.
• Do not line them all up the same way. Mix horizontals and verticals: an attentive opponent spots a habit very quickly.
• The 2-cell patrol boat hides anywhere — keep an isolated corner for it, it is almost always the last one found.

Two phases, two logics

• Search phase — you are trying to hit something. Spaced-out shots, maximum coverage.
• Destroy phase — you have scored a hit: now finish the ship. Fire at the four adjacent cells, then follow the axis as soon as a second hit reveals the direction.
• Never go back to searching before sinking what you have hit: a half-hit ship is information that goes stale.
• When a ship sinks, note its size: it tells you what remains to be found, and so which areas can still hold it.

The checkerboard method

• The smallest ship is two cells long. So it necessarily covers two adjacent cells.
• As a result, if you fire at every other cell, in a checkerboard pattern, you cannot miss a ship of two cells or more.
• That halves the number of shots in the search phase — fifty cells are enough to guarantee contact with every ship.
• Refine it: as long as only ships of three cells or more remain, you can space your shots one cell in three. Tighten the mesh as the big ships go down.

The mistakes that cost the most

• Firing at random. The checkerboard is almost twice as fast, for the same effort.
• Abandoning a hit to go and explore elsewhere.
• Placing your ships on the edges or in the corners. Statistically, that is where everyone looks first.
• Forgetting what you have already sunk. Once the aircraft carrier is down, no five-cell area needs searching any more.

Controls

Keyboard and mouse

• Placement: click to place a ship, right-click or the R key to rotate it.
• Firing: click a cell on the enemy grid. Cells already played are locked.
• Hits and sunk ships are marked distinctly.

Touch screen

• Drag a ship to place it, double-tap it to rotate.
• Tap an enemy cell to fire; a confirmation prevents accidental shots.
• On mobile, swipe to switch between the enemy grid and yours.

Frequently asked questions

How many ships, and what sizes?

Five ships: 5, 4, 3, 3 and 2 cells, making seventeen cells taken on a grid of a hundred.

Can ships touch each other?

Under the classic rules yes, but it is not recommended: sinking the first immediately reveals where the second is.

Can a ship be placed diagonally?

No. Only horizontally or vertically.

What is the best way to search?

In a checkerboard, one cell in two. Since the smallest ship covers two adjacent cells, this pattern cannot miss any of them, with half as many shots.

Do you fire again after a hit?

It depends on the variant. In the version used here you do not: each turn gives one shot, which makes the quality of each shot much more important.

More classics, free as well

• Belote — trumps, contracts, belote and rebelote
• Blackjack — twenty-one with virtual chips, no real money
• Checkers — the 10×10 board, mandatory captures and the majority rule