How to play Sea Battle

1 player vs computer, or 2 online

Sink all five of your opponent's ships by calling out squares on their grid, before they sink all five of yours.

The rules, step by step

1. 1

   Lay out your fleet: one ship of five squares, one of four, two of three and one of two. Each sits in a straight line, across or down, and they may touch but never overlap.

2. 2

   You start with a legal layout already on the grid. Tap a ship to pick it, tap a square to move it there, and Rotate turns it. Shuffle deals a new arrangement.

3. 3

   Once both fleets are down, take turns firing. Tap one square on the enemy grid per turn.

4. 4

   A shot is a hit or a miss and is marked on the grid. One shot per turn either way, so a hit does not earn you another go.

5. 5

   When every square of a ship has been hit it sinks, and you are told which ship it was.

6. 6

   Sink all five of the other fleet to win. Your own grid, beside the target grid, shows where you have been hit.

Three tips that change how you play

• Fire on a diagonal lattice while you are searching. The smallest ship is two squares long, so it has to cover at least one square where the row and column numbers add up to an even number. Half the board is enough to find every ship.
• Once you land a hit, finish the ship before you do anything else. Fire at the four squares around it until you get a second hit, then follow that line in both directions.
• Keep track of which ships are left. Late on, if only the five-square ship is still afloat, there are very few places it can be, and any run of five clear squares is the whole search.

Finishing a ship the right way

Say you hit at E5 while sweeping the lattice. Do not fire at F6 next, however tempting the diagonal looks: ships do not run diagonally, so a diagonal shot tells you nothing about this one. Fire at E4. If that misses, fire at E6. If that misses too, the ship must be vertical, so it runs through D5 or F5 and you have only two candidates left. Suppose E6 hits instead. Now you know the ship is horizontal and at least two long, so keep going that way, E7 and then E8, until you miss. Then come back and try E4 for the other end. Four or five shots and the ship is down and identified. The same hit poked at from all sides with no plan can easily cost you eight.

Three mistakes that cost beginners the game

Firing at every square in order, or at random.

Both waste about half your shots. A lattice pattern finds every ship in roughly fifty calls instead of a hundred, and it costs you nothing to use, because no ship can hide between the squares you are skipping.

Wandering off after a hit to try somewhere more promising.

A wounded ship is the best information on the board and it does not stay useful. Finish it, learn which ship it was, and take that ship out of your reckoning for the rest of the game.

Bunching your own ships in a corner, or lining them along an edge.

Edges feel safe and are not. An opponent who finds one ship on an edge has a very good idea where the rest are. Spread the fleet out, and mix the orientations so that a vertical hit does not tell them everything.

Common questions about Sea Battle