The Way of Go: Complete Guide

Game logic and computer opponent written by Claude Fable 5.1 specifically for TedPonderings.com.

1. The Objective

Go is a contest for control of the board. Two players take turns placing stones, and whoever controls more of the board at the end wins. You play Black and move first; the computer plays White.

2. The Board and Stones

Stones are placed on the intersections of the lines, not inside the squares, and that includes the edges and corners. Once placed, a stone never moves. It stays where it is unless it is captured. The marked dots are star points (hoshi); they are only reference marks.

3. Taking Turns

On your turn you either place one stone on any empty intersection where the move is legal, or you pass. There is no limit on how many stones a player may use.

4. Liberties and Groups

The empty points directly next to a stone, along the lines, are its liberties. Diagonals do not count. A stone in the middle has four liberties, on the edge three, and in the corner two. Stones of the same color that touch along the lines form a group, and the whole group shares its liberties and lives or dies together.

5. Capturing

When a move takes away the last liberty of an enemy stone or group, those stones are removed from the board as prisoners. A group with only one liberty left is in atari, meaning it can be captured on the next move.

6. Illegal Moves: Self-Capture

You may not place a stone where it, or the group it joins, would have no liberties. The one exception: if the move captures enemy stones, those are removed first, which opens up liberties and makes the move legal.

7. Illegal Moves: Ko

Sometimes a single stone is captured in a shape where the opponent could capture right back and repeat the position forever. This is a ko. The rule: you may not immediately retake a ko. You must play somewhere else first (often a threat your opponent has to answer, called a ko threat), and then you may retake on a later turn.

8. Life and Death

An eye is an empty point completely surrounded by one color. A group with two separate eyes can never be captured, because the opponent cannot fill either eye without committing self-capture. Such a group is alive. A group that cannot make two eyes and cannot escape or connect is dead, even if it is still sitting on the board. Beware of false eyes: an eye whose corners are held by the enemy can be collapsed.

9. Seki (Mutual Life)

Occasionally two opposing groups share liberties in such a way that whoever plays first there loses their own stones. Neither side plays, and both groups stay on the board alive. This is seki.

10. Ending the Game

The game ends when both players pass one after the other. Pass when you believe there is nothing left to gain. In this version every stone still on the board counts as alive, so actually capture any dead enemy stones before you pass. If White passes and you still see useful moves, keep playing.

11. Scoring (Area Scoring)

Your score = (your stones on the board) + (empty points surrounded only by your stones). Empty points touching both colors (dame) count for nobody. White also receives 7.5 points of komi as compensation for moving second; the half point means there are no ties. Prisoners are shown for interest but are not added to the score, because under area scoring a captured stone has already cost its owner a point on the board.

12. Playing This Version

• Learning / Intermediate: 9×9 or 13×13 board. Changing size starts a new game.
• Easy / Hard: Strength of the computer opponent. Hard thinks longer. You can switch at any time.
• Pass: Skip your turn. Two passes in a row end the game.
• Undo: Takes back your last move and White's reply.
• 🔮 Oracle: An optional advisor that ranks your best moves. See section 14.
• Save Progress: Keeps the current game on this device so you can come back to it.
• Markers: A red ring shows the most recent stone. A faint stone shows where you are about to play.

13. Advice for Beginners

• Corners first, then sides, then the center. Territory is easiest to surround where the edges help you.
• Keep your stones connected and try to cut your opponent's apart.
• Count liberties before you fight. The group with fewer liberties usually loses.
• Do not cling to a few doomed stones. Give them up and take something bigger elsewhere.
• Do not fill your own eyes or play inside territory that is already safely yours.
• A stone on the first line (the edge) is rarely useful early in the game.
• When your opponent's move does not threaten anything, play elsewhere and keep the initiative.

14. The Oracle

The 🔮 Oracle is an optional advisor for your turn. It never plays for you, and the computer opponent does not use it; it only helps if you ask.

When you press it, it plays hundreds of thousands of quick practice games from the position in front of you. Each practice game begins with a candidate move and is played to the end using this game's own rules: captures are answered, players never fill their own eyes, and the finished board is counted with area scoring and 7.5 komi. Moves that keep winning are explored more deeply. This method is called Monte Carlo Tree Search.

The leading moves, plus Pass, are then topped up until each one has at least 50,000 practice games behind it. The panel lists them from best to worst chance of Black winning, with a bar for each, and explains the best one in plain words. The top three board moves are marked 1, 2 and 3 on the board. Point at or tap any row to see where that move is.

The ± figure is the 95% margin. When two moves are closer together than their margins can separate, the Oracle says they are statistically tied, and either is a sound choice.

Moves are named with the usual board letters and numbers: columns lettered from the left (the letter I is skipped), rows numbered from the bottom.

The percentages are estimates from practice games, not guarantees. One figure is exact: after White passes, the Oracle tells you the exact final count if you pass and end the game.

On a phone the larger board can take a minute or so. The progress bar shows how far along it is, and closing the panel stops it.

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Japanese Glossary

• Agehama: Prisoners; captured stones.
• Aji: "Taste"; lingering possibilities left in a position.
• Aji-keshi: A move that needlessly erases your own aji.
• Atari: A stone or group with one liberty left; a threat to capture next move.
• Atsumi: Thickness; a strong wall of stones that radiates influence.
• Boshi: A capping play, placed above an enemy stone to block it from the center.
• Byo-yomi: "Reading the seconds"; overtime period in a timed game.
• Dame: Neutral points that belong to neither player.
• Damezumari: Shortage of liberties; being unable to make a needed move without putting yourself in atari.
• Dan: Master-level ranks, counting upward from 1-dan (shodan).
• Fuseki: The opening stage of the game.
• Geta: A net; a loose move that traps stones so they cannot escape.
• Goban: The Go board.
• Gote: A move that loses the initiative (requires no response).
• Hamete: A trick play that works only if the opponent answers wrongly.
• Hane: A move that "bends" around an opponent's stone.
• Hasami: A pincer; attacking a stone from both sides.
• Hiraki: An extension along the side of the board.
• Honte: The proper move; solid and patient, leaving no weaknesses.
• Horikomi: A throw-in; a sacrifice stone that destroys an eye or reduces liberties.
• Hoshi: Star point; the marked dots on the board.
• Ikken-tobi: A one-point jump; two stones in a line with one space between.
• Jigo: A drawn game (impossible here because of the half-point komi).
• Joseki: Established sequences of moves, usually in the corners.
• Kakari: An approach move against an enemy corner stone.
• Keima: The knight's move, shaped like the knight's jump in chess.
• Keshi: A reduction; lightly shrinking an enemy framework from outside.
• Kikashi: A forcing move that must be answered and gains something for free.
• Kiri: A cut; separating enemy stones from each other.
• Ko: "Eternity"; a repeating capture shape, and the rule that forbids retaking at once.
• Kodate: A ko threat; a move the opponent must answer, allowing you to retake the ko.
• Komi: Compensation points given to White for playing second.
• Komoku: The 3-4 point, a classic corner opening.
• Korigatachi: Over-concentrated shape; too many stones doing too little work.
• Kosumi: A diagonal move.
• Kyu: Student ranks, counting downward toward 1-kyu as you improve.
• Me: An eye.
• Miai: Two points of equal value; if one is taken, the other remains.
• Moyo: A large framework of potential territory, not yet secure.
• Nakade: A play inside an enemy eye space that stops it from becoming two eyes.
• Nigiri: Guessing odd or even stones to decide who plays Black.
• Nobi: A solid extension from your own stone.
• Nozoki: A peep; a move threatening to cut.
• Oiotoshi: "Connect and die"; stones that are captured even if they connect.
• Oki: A placement; a stone played at the vital point inside enemy shape.
• Ponnuki: The strong diamond shape left after four stones capture one.
• Sabaki: Light, flexible play that settles a weak group in enemy territory.
• Sagari: A descent; extending straight down toward the edge.
• San-san: The 3-3 point in a corner.
• Seki: Mutual life; neither side can attack without losing their own stones.
• Semeai: A capturing race between two groups short of liberties.
• Sente: The initiative; a move the opponent must answer.
• Shicho: A ladder; a zigzag chase that keeps the fleeing stones in atari.
• Shimari: A corner enclosure made with two stones.
• Tengen: The exact center point of the board.
• Tenuki: Ignoring the opponent's last move to play elsewhere.
• Tesuji: A clever, tactical "best move" in a local situation.
• Tsugi: A connection.
• Tsuke: An attachment; playing in direct contact with an enemy stone.
• Tsumego: Life-and-death problems, the classic way to study.
• Tsuru no Sugomori: "The crane's nest"; a classic capturing tesuji.
• Uchikomi: An invasion; playing deep inside an enemy framework.
• Uttegaeshi: A snapback; sacrificing a stone to immediately recapture a larger group.
• Warikomi: A wedge; playing between two enemy stones.
• Yose: The end game, where boundaries are settled.