Sea Battle
Find and sink your opponent's ships!
How to Play
Goal
Sink all 5 of your opponent's ships before they sink yours.
Placement
Place your ships on the 10x10 grid. You can rotate them or use random placement.
Shooting
Take turns firing at the opponent's grid. Hit = shoot again. Miss = opponent's turn.
Sinking
When all cells of a ship are hit, it's sunk and becomes visible.
Strategy & tips
Search in a chequerboard pattern. The smallest ship covers two squares, so no ship can slip between two diagonally adjacent cells. Firing at only every other square halves the shots needed for the search phase without any risk of missing a ship.
After a hit you switch modes: stop searching and start sinking. Fire at the four neighbouring squares, and as soon as a second hit reveals the orientation, follow that line to its end before returning to your search pattern.
Do not place your own ships along the edges or bunched together. Both are the common reflexes, and experienced opponents look there first. A ship in open water is statistically harder to find because it can be missed from more directions.
Track how many squares remain for each ship size. If only the five-square ship is left, you can rule out every area that no longer fits five contiguous cells — which often narrows the search to a handful of possibilities.
Variants
Salvo
Each turn you fire as many shots as you still have ships. Losing ships costs firepower, so a deficit becomes decisive quickly.
Moving fleet
Once per round an undamaged ship may shift one square. Known positions lose value and the search partly restarts.
No feedback
You are told only that you hit something, not which ship. Counting remaining squares becomes much harder.
How it works
1. Create a game
Click "Create Game" and receive a 6-digit code.
2. Share the code
Share the code with your friends – via WhatsApp, Telegram, or just tell them.
3. Play instantly
Your friends enter the code and you start playing immediately. No login required!
Origin
The game began as a pencil-and-paper pastime, commonly attributed to French soldiers during the First World War. It was played on squared paper long before any board existed for it.
In game-theoretic terms it is a textbook game of imperfect information: both sides know the rules completely, but neither knows the other's position. That structure is exactly what makes systematic search patterns so effective.
Frequently asked questions
How many ships does each side have?
Both players set up the same fleet, from one large vessel down to several small ones. Sink all of your opponent's ships first and you win.
Can ships be placed diagonally?
No, only horizontally or vertically. That is precisely why the chequerboard search works.
Can I fire at the same square twice?
Technically yes, but it always wastes a turn. The board remembers your shots and marks them.
Can we play across a distance?
Yes. Share the six-digit code and you play head to head straight in the browser, on any devices.