You and the computer each hide five ships on a 10x10 grid: Carrier (5 squares), Battleship (4), Cruiser (3), Submarine (3) and Destroyer (2). Ships lie horizontally or vertically, can't overlap, and may touch.
\nCoordinates: columns are letters A-J (left to right) and rows are numbers 1-10 (top to bottom), so B7 is column B, row 7.
1. Place your fleet. place carrier A1 horizontal puts the Carrier on A1-E1: a horizontal ship extends to the right of the square you give, a vertical one extends down. You can also give both ends (place destroyer C3 C4). Placing a ship again moves it, remove <ship> takes it off, and place random places all remaining ships randomly. The battle starts as soon as all five are placed.
2. Battle. fire B7 shoots at one square of the enemy grid. You're told hit or miss, and when a ship's last square is hit, which ship you sank (its squares are then marked as sunk). After each of your shots the computer fires once at your fleet, and you see where. You shoot first. You can list several targets in one command (fire B7 B8); they're fired one turn at a time.
The computer plays a strong but fair probability hunt: it only knows its own hits and misses, the squares of ships it has sunk, and which of your ships are still afloat. It never looks at your ship positions.
\nScore. Win: 100 + 2 points for every shot under 100 you didn't need (100 - shots fired, times 2) + 5 for each of your ships still afloat. Loss: 10 per enemy ship sunk + 1 per hit. resign ends the game with the loss score. When the game ends, the enemy fleet is revealed.