Go variants

There are many variations on the basic game of . Some are ancient digressions, whilst other are modern deviations. They are often to be found as side events at tournaments, for instance the , has a "Crazy Go" evening scheduled each year.

=Variants=

National variants

The difficulty in defining the rules of Go has led to a situation where there are many subtly different rulesets in existence. They are distinct over such areas as scoring method, ko, suicide, handicap placement and what to do about neutral points at the end of the game. In the main these differences are small enough to avoid changing the character and strategy of the game, so we do not consider them here. For more info refer to: Go rules.

There are some versions that are so distinct as to be considered variants. In other cases the effect of rule differences on actual play is minor, but for these the tactical consequences are substantive.

Tibetan Go

is played on a 17×17 board, six stones from each colour are placed on the third line, as shown. White makes the first move. There is a unique ko rule: ''one may not play a stone at an intersection where the opponent has just removed a stone''. This ko rule is so different from the other major rulesets, that it alone significantly changes the character of the game. Finally, a player who controls all four corner points gets a bonus of 40 points, and if he also controls the centre point he gets a further bonus of 10 points.

There is an additional rule for a subvariant played within Tibet. It is forbidden to play more than 2 intersections either from the last stone placed on the board, or from one of your own Bo.

Sunjang Baduk

A different form of Go evolved in Korea called sunjang baduk. What there is, tells us that has at least been played from the 7th century. Its most distinctive feature is the prescribed opening. The starting position dictates the placement of 16 stones as shown, and the first move is prescribed for Black at the center of the board. However, the counting system for determining territory at the end of the game also has some important differences. Namely, stones internal to territory and irrelevant to boundary definition, are removed before counting territory.

Variants altering the rules of play

First Capture

The first player to capture a stone wins. It was invented by Japanese professional Yasutoshi Yasuda who describes it in his book . Yasuda was first inspired by the need for a medium to address the problem of bullying in Japan, but soon found that "First Capture" also works as an activity with senior citizens and even developmentally delayed individuals. He sees it as a game in its own right, not just as a prelude to Go, but also as a way to introduce simple concepts that lead to Go. For the latter purpose, he recommends progressing to "Most Capture", in which the player capturing the most stones wins; then it is natural to introduce the idea of capturing territory, not just the opponent's stones. This variation is often called ''Atari Go'' in the West, were it is becoming increasingly popular as a preliminary means of introducing Go itself to beginners.

Environmental Go

, invented by Elwyn Berlekamp, adds an element of mathematical precision to the game. In lieu of playing a stone, a player may take the highest remaining card from a pack of cards valued in steps of ? from ? to 20: the player's score will be the territory captured, plus the total value of cards taken. In effect, the players participate in a downward auction for the number of points they think ''sente'' is worth at each stage in the game.
The professional players Jiang Zhujiu and Rui Naiwei played the first Environmental Go game in April 1998. Since then the variant has seen little activity on the international scene.

Cards Go

In players draw from a pack of cards contain instructions to play one of a fixed set of commonly occurring shapes. If the said shape cannot be placed on the board, then an illegal move is deemed to have been played: this necessitates resignation.

Multi-player Go

In ''Multi-player Go'', stones of different colors are used so that four players or more can play on one board.

Variants for more than two players, but not altering the mechanism of the game

Rengo

This involves two teams of players taking either the Black or the White stones. Each player in the team must play in turn, playing out of sequence will normally result in a small penalty . Partners may not consult on how to play, or engage in any form of signalling. Communication between partners may only take the following forms listed below.

* ''May we resign?'' can be answered with ''yes'' or ''no''
* ''How much time is left?''
* ''Whose turn is it?''

Pair Go

is a gender specific form of Rengo, calling for teams composed of one male and one female member. It was popularised by the Japan Pair Go Association as a means of increasing female participation in the game. They hoped that this increase in itself would add a new appeal to the game. They first introduced the variant to Europe at the 1992 European Congress in Canterbury, England. The International Pair Go Association sponsors an annual in Tokyo in November which has been running uninterrupted since 1989. The first professional Pair Go world championship was held in 1994.

''Note that BGA records suggest the first Pair Go tournament was held in 1991, which is a direct contradiction of the International Pair Go website''

Variants requiring a memory of the position

Blind Go

One or both of the players cannot see the board in this variant. Therefore they have to remember the whole position. This is considered much more difficult than playing blind chess. Indeed, most club standard players can play blind chess, but only professional players are able to complete a game of blind 19×19 Go.

One Color Go

Both players use stones of the same color. This variation is regarded as a useful tool for developing one's reading skills.

Variants with limited knowledge of the position

These variants are not purely strategic games, as the element of luck is quite important.

Shadow Go

This game requires two players, a referee and three playing sets. Each player sees only his own board, while the referee can see them both and also have his own set. Players place stones on their boards, with no knowledge of what other players are doing. A referee keeps track of the game on the central board. If any player makes an illegal move, the referee informs him about it . The player is allowed to make another move.

Rengo Kriegspiel

This is a crossover between rengo and shadow Go. There are four players, a referee and five Go sets. Each player has a limited knowledge not only about enemy stones, but also his teammate stones.

Non-standard boards

Although Go is most commonly played on a board with 19×19 lines, 9×9 and 13×13 boards are also available. They are used by beginners and by players who want a game that finishes more quickly. Due to flexibility of configuration, the two smaller sizes are more often played on the online Go servers such as KGS Go Server, which allows board sizes from 2×2 to 38×38.

The annual Milton Keynes Go Tournament has a popular side event which is played on a stylised map of Milton Keynes. The "Milton Keynes" board can be found , its non-conventional lattice presents some interesting possibilities. Another variant in this fashion is the .

A board is two dimensional surface with an implied third dimension because it is as if a standard board has been rolled and two opposite edges joined to form a tube and then the ends of the tube joined. It can be simulated on a standard 19×19 board, but requires imagination on the part of the players to perform an abstract join at the edges. It is noteworthy that the toroidal board has no corners, so standard joseki do not apply.

''TriGo'' is a go variant that uses a triangular-grid goban, where each stone has up to six liberties. To compensate for this, there are several rule changes: and superko are limited in scope, is not used, and after the first stone is placed, every turn consists of placing two stones. After both players have passed a turn, the score is counted , and in the case of a draw the player passing first wins.

Other than 2D

Alak is a Go-like game restricted to a single spatial dimension.

Go can be extended to . An example is , using the structure of a diamond crystal lattice. With many Go variants, the nature of the game changes dramatically if they do not keep the standard 4-connectivity of the points, which Diamond Go maintains.

Giog

Giog is a game played by two to four players. It can either be played for fun or as a serious competition. It contains a considerable amount of luck, strategic and psychological elements.

Equipment

Like Banqi, Giog uses Pieces. For Giog, it is important that the backs as well as the rims of the pieces be indistinguishable from each other so the pieces cannot be identified when face down. There are seven piece types in the game: Pawns, Cannons, Horses , Chariots , Advisors , Guards, Generals , respectively shown in the figure below. There are altogether 32 pieces and 2 colors. Let's say the colors are Red and Black.

Set Up

All players help to scramble the 32 pieces face down and distribute the pieces evenly to themselves. If the number of players is three, the winner of the previous game or a volunteer receives 12 pieces and the other two players receive 10 pieces each. Like a Mahjong game, each player arranges his/her pieces into one line with half of the pieces on top of the other half. Figure below shows how 3 players arrange their pieces.

The Ranking of Pieces

The ranking of pieces in Giog is identical to Banqi's ranking. That is, in ascending order:

* Pawns < Cannons < Horses < Chariots < Advisors < Guards < Generals.

The exceptions are: firstly, a black piece is always inferior than a red piece of the type.

* Black < Red.

For example, Red Horse wins Black Horse. And also, Pawns are inferior than Generals.

Determining the Order of players

Each of the players now reveals any one lower piece not in his/her own profile. He/she then places the revealed piece face up on top of the other face down piece. The ranking of the 4 revealed pieces determines the order of the players who revealed them. Should there be a tie among some players, they apply the same procedures again by revealing more lower pieces until the order is finally determined.

Choosing and collecting pieces

The first player starts to choose his pieces. He/she may only choose his pieces starting from a left or right head duo in any player's profile. He/she therefore has as many choices as twice the number of players. Following the first player, the second, third and fourth players consecutively collect their pieces, two at one time. The process is repeated until no piece , 2 pieces , 8 pieces are remained. These pieces are kept face down at a side and do not enter the game. Figure below shows John, having revealed a Black general starts to collect his first two pieces from no. 1 position. Kate who reveals a Red Guard collects the no. 2 duo. John misses the Black General but is consoled by the Red Guard at no. 7.

Playing the game

The first player plays his pieces first. He/she or any player who starts a new round may play the following 6 valid combinations of a same color:

* "Liab": Single. Any piece.
* "Dui": Double. Any 2 identical pieces.
* "Giog": A triple of a certain combination:
:* 1 Chariot + 1 Horse + 1 Cannon
:* 1 Cannon + 1 Advisor + 1 Guard
:* 1 General + 1 Guard + 1 Advisor
* "Sam Mui": 3 identical pieces.
* "Si Mui": 4 identical pieces.
* "Wu Mui": 5 identical pieces.

Each of the other players must play the same number of pieces. A player may play any pieces regardless of color or rank if he/she does not have the above valid combinations. The ranking of "Liab" is as before. Bear in mind that Black < Red. The ranking of "Dui" is same as the ranking of "Liab". The ranking of "Giog" is as follows:

*Chariot, Horse, Cannon < Cannon, Advisor, Guard < General, Guard, Advisor.

The ranking of "Sam Mui", "Si Mui" and "Wu Mui" are according to color, since only pawns are possible to form them.

The player who played the strongest combinations of a same type wins that round. If there is a tie, the round-starter always wins, or the order of players determines the winner. For example, if the first and fourth player play the same combinations, first player wins unless fourth player is the round-starter. The winner of a round collects the won pieces and starts a new round. The game is played until all pieces are exhausted. The winner will go to the player who wins most pieces.

Beheading the Cock

It is forbidden to play a General in the first or last round, either as a single piece or as part of a valid or non-valid combination. If a player is forced or tricked to play a general in the first or last round, then it is said that a cock is beheaded, and that player is considered the ultimate loser of the game even if he wins most pieces.

Fan-Tan

Fan-Tan, or fantan is a form of gambling long played in China.

History

Fan-tan is no longer as popular as it once was, having been replaced by modern casino games, and other traditional Chinese games such as Mah Jong and Pai Gow. However, it was once a favorite pastime of the Chinese in America. Jacob Riis, in his famous book about the underbelly of New York, How the Other Half Lives , wrote of entering a fan-tan parlor: "At the first foot-fall of leather soles on the steps the hum of talk ceases, and the group of celestials, crouching over their game of fan tan, stop playing and watch the comer with ugly looks. Fan tan is their ruling passion."

San Francisco's large was also home to dozens of fan-tan houses in the 19th century. The city's former police commissioner Jesse B. Cook wrote that in 1889 Chinatown had 50 fan-tan games, and that "in the 50 fan tan gambling houses the tables numbered from one to 24, according to the size of the room."

Fan-tan is still played at , where play goes on day and night, every day of the week, and bets can be made from 5 cents to 500 dollars.

The game

The game is simple. A square is marked in the centre of an ordinary table, or a square piece of metal is laid on it, the sides being marked 1, 2, 3 and 4. The banker puts on the table a double handful of small buttons, beads, coins, dried beans, or similar articles, which he covers with a metal bowl, or "tan koi".

The players then bet on the numbers, setting their stakes on the side of the square which bears the number selected. . When all bets are placed, the bowl is removed, and the "tan kun" or croupier uses a small bamboo stick to remove the buttons from the heap, four at a time, until the final batch is reached. If it contains four buttons, the backer of No. 4 wins; if three, the backer of No. 3 wins, and so on.

A 5% commission is deducted from the stake by the banker, and the winner wins three times the amount of his stake thus reduced.

Card game

Fantan is also the name of a card game, played with an ordinary pack, by any number of players up to eight. Once the deal has been decided, the cards are dealt singly, and any that are left over form a stock, which is placed face downwards on the table. Each player contributes a fixed stake or ante. The first player can enter if he has an ace; if he has not he pays an ante and takes a card from the stock; the second player is then called upon and acts similarly till an ace is played. This is put face upwards on the table, and the piles are built up from the ace to the king. The pool goes to the player who first gets rid of all his cards. If a player fails to play, having a playable card, he is fined the amount of the ante for every card in the other players hands.

The card game is also sometimes called 'Fan Tan'

Other uses

*''Fantan'' is also the for the Chinese fighter aircraft .
*''Fantan'' was a nickname given to Lon by Hud Bannon in the classic western film ''Hud''.
*''Fan-Tan'' is a 2005 novel that was conceived by actor Marlon Brando and director Donald Cammell in 1979.

Banqi

Banqi , or Half Chess, is a two-player board game played on a 4x8 grid, or half of the Xiangqi board. Most games last between ten and twenty minutes, but advanced games can go on for an hour or more. Banqi is a social game, usually played for fun rather than serious competition.

Equipment

Board

Although boards made specifically for Banqi exist, it is common to play on one half of the Xiangqi board .

Pieces

Banqi uses Xiangqi pieces. The backs of the pieces must be indistinguishable from each other so the pieces cannot be identified when face down. Pieces with international symbols printed on their backs are unsuitable. Each player controls five Soldiers, one General, and two each of the five other piece types, for a total of 16 pieces. In a typical set, one player’s pieces are red, and the other player’s pieces are black. The characters may also differ. For more detailed descriptions of the pieces used in this game, see the article.

Playing the game

The 32 pieces are shuffled and randomly allocated face-down to squares on the board. The pieces, as in , are placed inside the squares, rather than on the intersections as in .

The first player turns up a piece to begin the game. The color of that first uncovered piece is the color he or she will play in the game. The second player then makes a move, and the two alternate until the game is finished.

The game ends when a player cannot move, and that player is the loser. Most often, the game is lost because all of a player’s pieces have been captured and so he has no pieces to move. However, it is possible for one player to surround all of the other player’s remaining pieces in a manner that makes it impossible for them to move.

Rules for moves

There are three kinds of moves. A player may turn a piece face-up, move a piece, or capture an enemy piece. In some game variants, multiple captures may be made in one turn.

Turning over a piece

Turning a piece face-up is a legal move if there are any face-down pieces on the board. Once revealed, a piece may be moved, capture, or be captured. In some variants of Banqi, face-down pieces may also be captured.

Moving a piece

A player may only move face-up pieces of their own color.

Unlike Xiangqi, all pieces move identically: a piece may move only one square up, down, left, or right. A piece may never move onto a square that is already occupied unless such a move is a legal capture.

Note that all pieces capture the same way that they move, except the cannon in Taiwanese rules.

Capturing an opposing piece

A player may only capture with a face-up piece of their own color, and may only capture a face-up piece of the opposing color. In all captures, the captured piece is removed from the board and its square is occupied by the capturing piece.

The pieces are ranked, forming a hierarchy with the general at the top and soldiers at the bottom. Only pieces of equal or lower rank may be captured, with one exception. For instance, a chariot may capture a horse, and the general may capture either, but a horse cannot capture a chariot, and neither can capture the general. The one exception concerns generals and soldiers: the general cannot capture soldiers, and soldiers can capture the general. This reversal is reminiscent of Stratego.

In the Hong Kong version, the pieces are ranked in this order: general, chariot, horse, cannon, elephant, advisor, soldier. This ranking reflects the approximate value of the corresponding pieces in . All pieces capture exactly as they move: one square up, down, left, or right.

In the Taiwanese version, the ranking goes as follows: general, advisor, elephant, chariot, horse, soldier. This ranking is based on the initial board positions of the corresponding pieces in Xiangqi, though the horse and chariot are inexplicably swapped. Except for the cannon, pieces capture with the same motion as for movement: one square up, down, left, or right. The cannon is not included in the ranking because it is exceptional: it captures in an unusual way, it can capture a piece of any rank, and yet is vulnerable to capture by any piece except the soldier. A cannon captures as in Xiangqi: it moves any distance along a single row or column of the board, jumping over exactly one intermediate piece . Any other squares between the cannon and its target must be empty. The color of the screening piece does not matter; it may be friend or foe, or even face down. While a cannon may capture any piece, it must jump a screen to do so. Since a cannon must jump to capture, it cannot capture a piece in an adjacent square.

Another variation gives cannons the ability to capture soldiers and other cannons directly, without jumping over a screen. In other words, the cannon acts like the other pieces, ranking between horse and soldier, but with the added ability of capturing any piece by catapulting. Another popular rule allows the attempted capture of a face-down piece, which if it can be captured is done so. If the piece cannot be captured due to its rank or color, then it is left face-up, and no movement takes place. A further variation, popular with children, allows multiple captures on the same turn for already exposed pieces as well as face-down pieces as long as they are successful.

Stalemate

A stalemate threat occurs when one player forces an endless cycle of moves. In a typical stalemate, the instigator repeatedly attacks, but cannot capture, an enemy piece. The legality of stalemating varies by culture:

* Some players consider stalemate illegal. This is consistent with the rules of , which require the instigator to cease the continual attack, else the victim wins.

* Some players consider stalemate a legal strategy. The ability to instigate a stalemate in an otherwise losing game is one of the ways that skill can overcome luck, since the victim must accept either a drawn game or the loss of a piece. Handling a stalemate situation requires skill for the winning player, as well — the necessity of heading off a potential stalemate adds spice to an otherwise overwhelming victory. And deciding whether you can still win, even without that piece, requires great expertise.

Games in which stalemate is allowed tend to produce much more even games — many a lopsided game is turned into an interesting match by the surrender of a piece to avoid a stalemate.

Strategy

* Early Action - Under Taiwanese rules, playing first is a slight disadvantage. If you turn up a cannon, the opponent can turn up next to it with a high likelihood of capturing the cannon and ''no'' risk of losing his piece to the cannon. If you turn up anything else, the opponent can turn over a piece one hop away. If he finds a cannon, it can take your piece, but no matter what it is, your piece can't immediately take his. By convention, the new challenger plays first to give the previous game’s loser a slight advantage.
* Chance - It is difficult to form strategy early on, since all pieces are hidden. This is a disadvantage to experienced players, who cannot follow a formulaic win strategy.
* Royalty - Incidentally, the life of the general is not the point of this game; the game does not end because of the general’s death. In fact, both generals usually die long before the end of the game. The game ends only when one player has no legal move. Banqi is often a game of attrition.
* Soldiers - Since there are five opposing soldiers, the mighty general is perversely vulnerable, and frequently the general turns out to be worthless in the face of a soldier front. This vulnerability makes the second-highest rank, chariots in Hong Kong or advisors in Taiwan, the most powerful pieces in many games.
** It is often advantageous to search out and destroy the enemy soldiers, which the opponent may overlook as less valuable pieces. Once the enemy soldiers are eliminated, the general can roam free across the field in relative safety, vulnerable only to attacks by cannons and the opposing general.
* Chariots- Chariots can capture any piece by moving any number of spaces on the board, like rooks in Western Chess. However, they can only do this when capturing a piece.
* Cannons - Under Taiwanese rules, the cannon has devastating potential if it is well placed behind a shield of strong allied pieces. Given such position, a cannon can be stronger than either general or advisor, especially if the opposing general and/or advisors have limited lateral mobility—that is, if they can’t sidestep a cannon attack. On the other hand, the opponent has plenty of pieces that can capture the cannon if only they can get next to it, so a poorly placed Cannon is usually short-lived. Most players will readily sacrifice a horse, chariot, or elephant to capture a cannon.
* Hidden Pieces - Play is often directed by the face-down pieces. Pieces are vulnerable in a dead-end “tunnel” , in which there is no escape from a pursuing enemy piece.
**If there is enough space between you and the attacker, you will have time to turn up some face-down pieces before the attacker closes on you. If you get to an open area at least 2 x 2 in size, you can use that “rotation space” to dodge a single enemy piece by sidestepping. You can sometimes create a rotation space by turning up a smaller enemy piece on the inside corner of a bend in the tunnel, or you might be able to punch through a wall of the tunnel to reach an open area on the other side.
**It is often important to keep track of what pieces are still face-down. Usually this is done by checking both the “graveyard” for dead pieces and the playing field for live pieces; by the process of elimination you can figure out what must still remain.
* Resignation - A player may simply resign if the game seems lopsided.
* Attrition - Exchanging equal pieces is usually to the advantage of the player who is ahead. When winning by a sufficient margin, even disadvantageous trades can accelerate victory if chosen carefully.
* Objective - Often, the move that will win most quickly gives away the most valuable piece. Such moves are often overlooked.
* Evasion - Some players derive pleasure from making it as difficult as possible for the opponent to actually coerce the win. Others make a game of seeing how many opposing pieces they can capture before their demise. Some just resign when defeat becomes evident, and start a new game.
* Parity - Parity is important, especially in the end game. In situations where only an opposing King and pawn are left with one space between, turn order invariably determines the winner. The pawn's move will produce a stalemate, while the King's move will result in his inevitable capture.
* Pinning - It is fairly easy to pin a piece against the edge of the board. Frequently, being pinned or not is the difference between defeat and stalemate.