Glossary gives brief explanations of some of the most often used Go terms and concepts.  These terms are characteristic for the Go-related language, and are essential for it's understanding.  Italicized words are transliterations of the corresponding Japanese terms.

Alive

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A B

A group of stones is said to be "alive" if it can't be captured by the opponent (at least at the time of group evaluation).  Position on the left shows an absolutely "alive" white group – it is separated into two completely encircled areas ("eyes") – points A and B and as such can't be captured under any conditions.  However, in most cases groups are less formidable and their characteristic of being "alive" is a relative one, and depends on many circumstances.  (See discussion of Territory for more details about "life" and "death" in Go.)

Atari

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A A A A

An immediate threat of capture, i.e a situation when a stone or a group of stones have only one liberty left.

Critical (vital) point

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A

A point within the group of stones that separated this group into two completely encircled areas ("eyes").  E.g., for white group on the left point A is the critical (vital) point.  White move into this point turns white group into absolutely "alive" group.  Black move into this point turns white group into a "dead" group.  (See discussion of Territory for more detailed description.)

Cross-cut

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C

A move placed in a cross-cut pattern.

Dame	Go to:  Glossary top | Previous term | Next term | Glossary bottom

D

While literally meaning "liberty", dame is used most often to refer to the neutral point (or points) between "alive" groups of opposite colors.  It's a standard practice to fill dame points by play stones of any color after game completion in order to simplify territory counting.

Dead	Go to:  Glossary top | Previous term | Next term | Glossary bottom

C

A group of stones is said to be "dead" if it can't be saved from capture by the opponent (at least at the time of group evaluation).  Position on the left shows a "dead" white group – it is completely encircled by black stones and has no room to get two "eyes" (Black stone C occupies the only critical point within White's group).  The characteristic of being "dead" is a relative one, and depends on many circumstances, e.g., on the potential ability of White to capture the encircling black stones.  (See discussion of Territory for more details about "death" and "life" in Go.)

Eye	Go to:  Glossary top | Previous term | Next term | Glossary bottom

A B

"Eye" or me is an area within the group that is completely encircled by the stones of that group.  The ability of isolated groups of stones to survive is directly related to their ability to get at least two "eyes", which make them invulnerable to opponen's attack.  Position on the left shows an absolutely "alive" white group – it has has two "eyes" – points A and B, and as such can't be captured under any conditions.  (See more about "eyes" in the discussion of Territory in Go.)

Handicap

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H

Handicap is a way to achieve a balance (or at least its proximity) between opponents of different strengths.  Balance in general is very important in Go.  Balance between attack and defence, between territory and influence, staying connected and trying to expand, etc.  One of the most important types of balance is a balance between opponents' strengths.  Unbalanced game is of a little interest to all: stronger player doesn't have to apply real effort to win, weaker player has no chance no matter what effort he puts in, spectators get bored pretty soon. To make games between opponents of different strengths meaningful Go employs a system of adjustable handicaps.  Handicap value is expressed as a number in the range from 1 to 9 that is determined basing on the history of games (there exist several systems of deriving handicap from the history of games).  Handicap 1 means that the weaker player gets the Black (makes the first move), and doesn't give Komi to the White.  Starting with handicap 2 black stones are placed into the predefined board locations before the start of the game (White makes the first move in this case).  Number, locations and order of handicap stones incremental placement depend on the size of the board and are different for 19x19, 13x13 and 9x9 boards.

Hane	Go to:  Glossary top | Previous term | Next term | Glossary bottom

H

A move bending around opponent's stone (in relation to existing stones).

Horikomi

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H

A "throw-in", i.e. a move involving the sacrifice of a stone to force the opponent's stones to take a bad shape (most often preventing him from connecting at the right point).

Hosi	Go to:  Glossary top | Previous term | Next term | Glossary bottom

A "star" point — one of the predefined points on the board where the handicap stones are placed.  Number and location of Hosi points depend on the size of the board, and are different for 19x19, 13x13 and 9x9 boards.

Keima

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K

A knight's move extention.

Ko	Go to:  Glossary top | Previous term | Next term | Glossary bottom

X 1

The Ko rule (Basic rule 8) serves to prevent the possibility of endless recaptures (one possible position is shown on the left) that might otherwise tie the game.  Ko rule prohibits to make a move that results in a repetition of position (stone allocation) on the entire board.  This prohibition results in an opportunities for each player two make two moves in a row in certain local positions.  (See discussion of Ko-fight for more detailed description.)

Ko-fight

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A fight between Black and White characterised by an ability of each side to play two moves in a row in certain local positions using Ko-threats to prevent an opponent from making moves undesired for the player.  (See discussion of Ko-fight for more detailed description.)

Ko-threat

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A B

A local position where the potential ability of a player to make two moves in a row due to the Ko-fight can provide a significant gain (usually in terms of saving own group of stones or caturing one of the opponent).  E.g., in the position shown here it takes two Black moves in a row (to point A and point B as one possibility) to save black group of stones in this corner.  (See discussion of Ko-fight for more detailed description.)

Komi	Go to:  Glossary top | Previous term | Next term | Glossary bottom

Compensation for the right of the first move that Black gives to White in an even (without handicap) game (Basic rule 4).

Liberty

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X X X X X Y Z Y O Y Y

Liberty or "breath" or point of liberty/"breath" is an unoccupied horizontal or vertical point directly adjacent to the stones of a group. Position on the left shows that black group of 5 stones has 5 liberties marked by X.  White group of 3 stones also has 5 liberties – 4 points marked by Y and 1 point marked by O.  Isolated white stone has 2 liberties – 1 point marked by Z and 1 point marked by O Number of liberties of the group is the most obvious measure of the ability of that group to survive (in order to capture the group the opponent must take the last point of liberty of that group).  (Number of liberties is not the only measure of survival ability – stone shape, location, and surroundings are also extremely important for the ability of the group to survive.) Number of liberties of the group related to the number of stones forming the group is also an obvious (though not the only) way to evaluate relative group effectiveness.  For example, in the position shown here both 5-stone black group and 3-stone white group have 5 liberties each.  White group is more effective relative to black group, since it took 2 moves less to build it, while it has the same number of liberties.

Nidan bane

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H H

Two succesive Hane moves.

Ogeima

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O

A large knight's move extention.

Prisoner

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A stone that has been captured and removed from the board.  Term "prisoner" is also often applied to the dead (especially isolated) stones on the board.  Each prisoner stone is worth one point to the player who captures it.  During the commonly accepted procedure of territory counting prisoners are placed into opponent's territory – since only free points count, each prisoner reduces opponent's territory by one point (this is done to simplify territory counting).  Prisoners can be exchanged during the game to provide each player with additional playing stones.

Sagari

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S

To "hang down" or "descent" — a move extending toward the edge of the board.

Seki	Go to:  Glossary top | Previous term | Next term | Glossary bottom

B A

Seki or "dual life" is a position in which stones of both players are mutually isolated, and are without two "eyes"; yet they are still "alive", since an attacking move of either player leads to his loss in this position.  Which means that generally none of the players will make a move here, and position will remain as-is until the end of the game (unless used by one of the sides as a Ko-threat during a Ko-fight). In the position on the left both white and black stones are in fact "alive" while points A and B are "neutral" (dame).  Technique of building a Seki permits to get "live" groups within opponent's territory when it's impossible to build a group with with two "eyes".  (See discussion of Territory for more details about seki.)

Semeai

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W W W W B B B

A local race to capture, i.e. a situation when groups of stones of both colors are mutually isolated from their main forces (can't be saved by connecting), and have no room to make two eyes (a self-sufficient living shape).  The only way to save each group involved in semeai is to capture one of the opponent.  Position on the left shows black group of 3 stones (marked by B) and white group of 4 stones (marked by W) where the only way for each group to survive is to capture the opposing group of stones.

Tsuke

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T

A move made in contact with one of opponent's stones, but not in contact with any friendly stones.

Warikomi

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W

To "thrust" or "squeeze into" — a move made between opponent's stones in order to separate them or/and to connect one's own stones.

Watari

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W

A "bridge", i.e. a low move connecting underneath or along the edge of the board.