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Primer · 01

How to Play Cell Division

//5 min read//Cell Division

Cell Division is a game about turning empty squares into connected territory. Two players place cells, cells grow into clusters, and whoever ends the game with more points wins. The rules fit in a paragraph. The depth comes from what you do with them.

Place a cell, score its connections

Players alternate placing one cell per turn on any empty square. Cells connect to same-color neighbors in all eight directions — horizontal, vertical, and both diagonals. Scoring is almost embarrassingly simple:

Those four axes — |, —, \,/ — are the whole engine of the game. Every decision you make comes down to which axes you're activating for yourself and which ones you're denying to your opponent.

→
4
4
4
2
2
1
+8
+6
+12
Mid-game on a 3×3 board. Each placed cell shows its current score; empty squares show the delta the current player would gain by playing there. The +12 in the bottom-left is the new cell (6 points) plus the three green neighbors each gaining an axis (+2 each).
Green12Cyan5

Clusters are worth more than the sum of their cells

The lead gap balloons the moment you start building shapes instead of placing single cells. Say green takes the (0,2) hint and forms a 2×2 block. Every cell in that block now touches three neighbors along three distinct axes, so each one jumps from 4 points to 6.

→
6
6
6
6
2
2
1
+2
+9
Green places at (0,2), closing a 2×2 block. Every cell in the block now lights up three axes — green's total jumps from 12 to 24 with a single move.
Green24Cyan5

A single well-placed cell can double your score when it closes a shape. This is the whole strategic lever of Cell Division: look for the cell that fills an axis for multiple neighbors at once.

The game ends when the board is full

There are no captures, no timers, no resignations. When every square is occupied the game ends and the player with more points wins. That's it. Here's the same 3×3 board fully played out.

→
4
6
8
6
6
4
4
4
2
Final board. The center cell picks up all four axes for the full 8-point ceiling; green edges out cyan by more than 2x.
Green30Cyan14Winner Green
END · STATE

Four AI opponents, four different brains

The AI ships in four tiers, each with its own personality. They all run locally in JavaScript — no server, no WebAssembly, no GPU — and they all respond between taps.

One more rule: the mirror forfeit

On a symmetric board, the second player could theoretically guarantee a draw by reflecting every move the first player makes. Cell Division detects five types of mirror strategies — vertical, horizontal, both diagonals, and 180° rotation — and if every second-player move mirrors the first, they forfeit immediately. It keeps the game honest.

That's the whole game. If you want to go deeper, the strategy post on claiming the interior covers why corners cap at 6 and how the 1-away pivot captures territory. And the AI post walks through the 14 features and training loop behind the Hard and Elite tiers.