Go Rules in Plain English: Liberties, Capture, Atari, Ko (Explained)

Read time: ~7 min · Updated: July 2026 · Part of: Learn Go

Go has a strange reputation: "the hardest game in the world." Yet the whole ruleset is one of the shortest in all of board gaming. This article lays out the complete rules in plain English — liberties, placing stones, capture, the no-suicide rule, the ko rule, and how a game is decided — with one summary table you can come back to any time.

【Terms used in this article】

1. The board and the stones 🎯

Go is played on a grid of lines. Stones go on the intersections, not in the squares (this is the first difference from chess or checkers).

• A standard board is 19×19 (361 points), but Go is still Go on 13×13 or 9×9, and brainGO distills it to 4×4 (16 points).
• One player uses black stones, the other white. Black always plays first.
• Every stone is identical — there are no "types" of pieces and no special movement to learn.

🧩 The whole game is about position. Because every stone is the same, the only thing that matters is where a stone sits and what's next to it.

2. Rule 1 — Place a stone, count its "liberties" 🫁

On your turn, you place one of your stones on any empty intersection. That stone now has liberties: the empty points directly touching it, up/down/left/right.

• Diagonals do not count as liberties.
• A lone center stone has 4 liberties; a corner stone has only 2.
• Same-color stones that touch orthogonally form a group, and the group's liberties are all the empty points touching any of its stones.

🫁 Life analogy: a liberty is a stone's breath. A lone stone in the middle of the board can breathe on four sides. A stone in the corner can only breathe on two. Want the deep version? → What is a "liberty" in Go?

3. Rule 2 — Capture: fill the last breath 🎯

This is the only rule that actually removes stones from the board.

When you place a stone that fills the last liberty of an enemy group, that group is captured — removed immediately. You can capture several groups at once if your single move fills the last liberty of each.

🐬 Life analogy: capture is like a slow surround in water. You don't hit the swimmer — you quietly cut off every direction they can breathe. The moment their last breath is gone, they're out.

A group with exactly one liberty left is in atari — the alarm state. On the next move, the opponent can fill that last liberty and capture it. Hearing "atari" should feel like hearing a fire bell.

4. The no-suicide rule 🚫

You cannot play a move that leaves your own stone (or group) with zero liberties — unless that same move also captures an enemy group.

• Pure suicide (your stone dies, nothing captured): illegal, you can't play it.
• "Suicide that captures": your stone looks breathless, but it also fills the enemy's last liberty — the enemy is removed first, and now your stone has liberties and lives. This is legal.

🛡️ Memory hook: capture always beats suicide. If your move captures anything, it's legal — even if your stone looked like it was suffocating. The enemy stones come off first, which may give your stone air.

5. The ko rule 🔔

Without this rule, two moves could loop forever. The ko rule forbids immediately recreating the exact board position from one move ago.

Here's the classic setup:

• You capture a single White stone.
• White can immediately recapture your stone in the same spot — restoring the board to exactly how it looked before your move.
• If that were allowed, you two could capture back and forth forever.

So Go adds one line: you may not make a move that exactly repeats the board position from your previous turn. White must play somewhere else first; only later can they come back to that spot.

🔔 Life analogy: the ko rule is like a "no-takebacks" rule in a card game. You just made a move; the opponent can't instantly undo it and put everything back. They have to do something else first.

On brainGO's 4×4 board, the ko rule matters in one specific shape (a single-stone recapture loop). The solver enforces it automatically, so you don't have to remember it — you just won't be allowed to retake illegally.

6. How a game is decided (and why brainGO skips this) 🏁

In full 19×19 Go, the game ends when both players pass. The winner is decided by territory + captured stones: whoever surrounds more empty points (plus captures) wins. There's a small "komi" bonus to White for moving second.

brainIGO skips all of this — deliberately. Scoring, territory counting, and endgame math are exactly the parts that bury beginners. Instead, brainIGO focuses on the part that transfers to every later stage of Go: pure capture puzzles on a 4×4 board. The goal isn't "who wins the game" — it's "can you find the move that captures within a few moves, and is your reading correct?"

7. One-table summary of the rules 📋

If you remember only one thing from this article, make it this table.

8. A worked capture, in four moves 🧩

Picture a White stone in the corner with two empty neighbors. It starts with 2 liberties.

1. Black plays next to it → White drops to 1 liberty → White is in atari.
2. White extends (adds a stone that touches the original), giving the group new air → back to a safe liberty count.
3. Or White ignores the alarm and plays elsewhere → Black fills the last liberty → White is captured, removed from the board.

The entire arithmetic of beginner Go is in those moves: liberties minus filling moves. No numbers beyond counting visible breaths.

🎯 The reflex that transfers everywhere: before you play, glance at the target group's liberties. That single habit — counting breath — is the foundation of every later skill in Go.

9. brainIGO's 4×4: capture puzzles, proven correct 🎯

Here's the honest scope of what brainIGO does with these rules:

• 4×4 board, 16 points. Stones touch on move one — no opening theory needed.
• Pure capture puzzles. The goal is always: find the move that captures at least one enemy stone within N moves.
• An exact solver proves every answer. Because the board is tiny, the solver can search every possible continuation — the "winning move" you're shown is provably correct, not a human guess.
• The ko and no-suicide rules are enforced automatically. You don't have to memorize them — the engine simply won't let you make an illegal move.

This is why brainIGO focuses on capture alone and skips territory, scoring, openings, and endgame: those are the parts of Go that bury beginners. Capture is the skill that transfers; everything else is layers on top.

🧠 What about brain benefits? Go is a calm visual-logic exercise with zero number anxiety. Many apps claim brain games "prevent dementia" — the evidence there is still inconclusive. What we can say plainly: Go keeps your mind active, and a daily puzzle is a good habit. That's the honest claim.

Start playing

The rules above are everything you need. The fastest way to feel them is to capture your first stone in 30 seconds — the companion handles the rest.

👉 Play brainGO — your first capture puzzle

Related guides

• Learn Go: the visual beginner's guide — the same rules, with pictures
• What is a "liberty" in Go? — the one concept behind every capture
• Capture Go training — turn these rules into a reflex