How to play weiqi: rules, captures, ko, seki, and scoring

Weiqi — also known as Go, baduk, or 碁 — looks intimidating from the outside: a 19×19 grid, black and white stones, decades of strategy books. But the rules fit in a single page. Everything else is judgement. This guide walks you through the rulebook in the order you actually encounter it when you sit down at an empty board, so that by the time you finish reading you can play a complete game and score it correctly.

If you are looking for the historical and cultural context behind the game, start with What is weiqi?. For a deeper look at how a position becomes a winning position, see Basic weiqi strategy.

● The board

01

The board, the stones, and the players

A 19×19 grid is the standard, but smaller boards are also legal.

The standard board has 19 horizontal lines and 19 vertical lines. The intersections — not the squares — are where stones are played. There are 361 of them.

Both players begin with the same supply of stones: 180 black and 180 white. Games almost never use all of them; a normal 19×19 game places roughly 200–300 stones in total.

The lighter-coloured player (White in most rule sets) plays second. Black plays first. The convention varies by tradition — in Chinese and Japanese rules Black is conventionally first, in some handicap formats White plays first — but for almost every friendly and competitive game you will encounter in 2026, Black moves first.

● Placing stones

02

How a turn works

Place one stone on an empty intersection, then resolve captures.

On your turn you do exactly one of the following:

1. Place a stone on an empty intersection. Stones are never moved once placed — only added and removed.
2. Pass your turn, signalling that you believe no useful move remains. Two consecutive passes end the game.

Once you place a stone, any opponent stones that now have no remaining liberties are removed from the board. These are called captures. Your own stones can also be captured if a placement leaves them with no liberties — see suicide below.

● Liberties

03

Liberties: the one rule that matters

Every stone has liberties. Remove them all and the stone is captured.

A liberty is an empty intersection directly adjacent to a stone (horizontally or vertically — diagonals do not count). Every isolated stone has four liberties. Stones of the same colour that are connected in a chain share liberties — the liberties of the chain are the empty neighbours of any stone in the chain.

If at the end of your turn an opponent’s chain has zero liberties, that chain is removed and placed in your prisoner pile. This is a capture.

The simplest example: place a white stone completely surrounded by your black stones. After you complete the encirclement, the white stone has zero liberties and is removed.

● Two key edge cases

04

Suicide and the ko rule

The two restrictions every beginner trips over.

Suicide. A move that places a stone with no liberties of its own (and that does not capture anything) is illegal under Japanese, Korean, and most modern rules. The exception is Chinese rules, where suicide is legal. Most online servers — including sharp.go — use Japanese or Korean rules, so you cannot suicide.

The ko rule. A situation may arise in which the same board position could repeat indefinitely: you capture a single stone, and your opponent immediately recaptures it, which would let you recapture again. This is called a ko. To prevent infinite loops, the ko rule forbids immediately recreating a position that existed previously in the game. If you captured at A, your opponent cannot immediately play at A back; they must play elsewhere first.

For more complicated repetitions (the superko), a 32-bit Zobrist hash is used by some engines — see the inside-the-engine post for how sharp.go detects this at scale.

● Passing

05

When the game ends

Two passes, resignation, or a referee stopping play.

The game ends in one of three ways:

1. Both players pass consecutively. This signals mutual agreement that neither side can improve the position. The board is divided into territory and counted.
2. One player resigns. A resignation counts as a loss for the player who resigned and a win for the opponent. White scoring systems adjust the margin slightly.
3. A referee stops play. In formal tournament settings a referee can declare the game finished if the position becomes obviously settled (for example after a loop of passes with no captures).

● Counting

06

How to count the result

Territory plus captures, with komi balancing Black's first-move advantage.

There are several counting systems. The two most widely used are:

Japanese / Korean counting (area scoring, simplified). Each player counts:

• The empty intersections they surround at the end of the game (their territory).
• The number of stones they still have on the board.

The player with the higher total wins. To balance Black’s first-move advantage, White receives komi: a compensation of 6.5 points (Japanese rules) or 7.5 points (Korean rules). The half-point prevents ties.

Chinese counting (territory scoring). Each player counts only the empty intersections they surround. Captured stones do not count for the capturer — instead, the opponent’s dead stones (stones that will inevitably be captured, even though they are still on the board) are removed and counted as the capturer’s territory. Komi is typically 7.5 points.

● Seki

07

Seki: the rule that makes weiqi deep

Mutual life: two groups facing each other across empty space.

A seki is a position where two opposing groups face each other across empty intersections with no captures available — and any move by either side would result in self-capture. In seki, both groups are alive with zero territory between them. The shared empty points are not counted for either player.

Seki is rare at the beginner level but begins to appear within the first 30–50 games you play. Recognising when a local shape is seki (and therefore no further play is needed there) is one of the hallmark skills of an intermediate player. sharp.go’s analysis engine flags seki positions by default.

● Living and dying

08

Life, death, and the two eyes

A chain is alive if it can make two eyes. Otherwise it can be killed.

The deepest rule in weiqi is also the simplest to state: a chain is alive if it can guarantee two separate empty spaces inside its own territory. These are called eyes. With two eyes, an opponent cannot fill one without atari-ing the chain in a way that requires playing into the other eye — which is suicide and illegal.

A chain with only one eye can be captured by forcing the opponent to play inside and then filling the eye. A chain with no eyes is in atari the moment it has only one liberty and dies on the next move unless it expands.

Strong players read life and death by counting liberties and eyes several moves ahead. This is what the game is actually about.

● Frequently asked questions

01 How many intersections are on a weiqi board? ▾

A standard weiqi board has 19×19 = 361 intersections. Stones are placed on intersections, not inside squares. The 9×9 and 13×13 boards are also legal and use the same rules.

02 Can you capture a whole group at once? ▾

Yes. A chain is removed from the board when it has zero liberties — the same as a single stone. Capturing multiple chains in a single move is called a double-atari or a crane's nest depending on the shape.

03 Is suicide ever legal? ▾

Under Japanese and Korean rules (the most common rule sets in 2026) suicide is illegal — you cannot place a stone that has no liberties and does not capture. Under Chinese rules suicide is legal. Check the rule set your tournament uses.

04 What is komi and why is it 6.5 or 7.5? ▾

Komi is a points compensation awarded to White because Black moves first. 6.5 points (Japanese) or 7.5 points (Korean) reflects how much of an advantage the first move has been measured to give. The half point prevents ties.

05 Where can I play free weiqi online? ▾

[Sharp.go home](/) hosts a free browser-based 3D weiqi client. You can play against a calibrated AI at any level, or take turns with a friend on a shared link.

● Where to play

Your first game

Free browser board, calibrated AI, no install.

Now that you know the rules, the fastest way to internalise them is to play. Sharp.go runs entirely in the browser — open the game, pick a 9×9 or 19×19 board, and play against a calibrated AI that will capture your mistakes early without punishing every casual experiment. A 19×19 game takes 20–40 minutes; a 9×9 game takes 5–10.

For the strategy that comes next, see Basic weiqi strategy. For context on why this four-thousand-year-old game is still being played and engineered in 2026, see What is weiqi?.