The games currently supported by Gorrion are Backgammon, Breakthrough, Chess, Go, Havannah, Hawalis, Hex, JadeJack, Kauri, Margo, Merels ( Nine Men's Morris, Morabaraba ), Onyx, Othello ( Reversi ), Pente, Toguz Kumalak, Unlur, Viking Tafl ( Brandubh, Tablut, Tawlbwrdd ) and Y. Here are short descriptions of each of these games, together with links to the full rules.

Backgammon

( Here are the rules for play on Gorrion. They have been altered slightly to improve play in correspondence mode. )

Matches are played over several games. Points matches can be played with or without the doubling cube. Money games are played with the cube and can be played with or without the Jacoby rule. Games are started automatically when the previous one ends. To get a speedy transition the first move in the new game is given to the player who makes the last move in the previous game. You may leave a match at any time. If you forfeit in any of the games of the match then the match will terminate.

Extraordinary Rules. You may not 'double' if you are in a shut-out position with no possible move. This rule appears to be followed nowhere else, but will avoid the delay of an empty turn going to your opponent and back again. You may not 'double' if the current game stake is sufficient for you to win in a points match. The Crawford rule applies: the game immediately following the one in which either player gets to one point of the winning score will be played 'non doubling'.

Board Setup. White always has the first move in the first game of a match. Positions are numbered 1 to 24 from White's inner table round to Black's inner table. The board in your games will always have your table at the bottom. When viewing other games the table of the player who has the move will show at the bottom.

Links, Backgammon articles. Here are some links and articles on Backgammon that I have found to be useful.

Brandubh, Tablut, Tawlbwrdd

These games are modern reconstructions of a class of games played during Viking times. The King, with the help of his men, needs to reach safety ( board edge ) without being captured. The games will be played under the rules as given on my Hnefatafl web page. The rules being as I understand them from the World Tafl Federation pages. Brandubh will be played under the 'double weak king' rule.

Breakthrough

Players aim to be the first to get a pawn to reach the back row. Pawns move either one place forward, or diagonally one place forward. Captures are made like pawn captures in Chess, diagonally.

Double Pawn Move. Games on Gorrion will be made with a change to the rules. Pawns on the first and second rows can move forward two places.

Castle Variation. The option is available to have a different pawn setup, to get a speedier start to the game.

Go

Go is the classic game of territory. It is one of the oldest board games known. Players take turn to create areas of territory and at the same time to form secure groups of stones. Captures of unsecured groups of stones can be made. This is a professionally played game, enjoyed throughout the word. Only the board size of 19x19 is played here. Games here are played with Japanese rules. Komi is 6.5.

[ Introduction to Go ]   ( external site )

Havannah

Players aim to form one of three types of connection: an enclosing circuit, or a link that connects any two corners of the board or one that connects any three edges. A game is drawn if neither player is able to form a connection. This is possible, but rare.

[ Full rules for Havannah ]

Hawalis

This is a seeding game of the Mancala and Bohnenspiel family. Each player starts with two stones in each pit on their side of the board.

Seeding. In turn each player chooses a pit that contains at least two stones, takes all the stones and seeds them anticlockwise to the rows of their table. The stones are seeded one by one, starting with the next pit. If the final stone lands in a pit that is occupied, the stones from that pit are taken up and also seeded. You continue seeding until the final stone lands in an unoccupied pit. If no pit contains at least two stones you may choose a pit that contains a singleton stone, but only if the next pit is unocuppied.

Capture. Captures are made when the final stone is placed. If it is placed in the inner row of your table and your opponent has stones in the pit opposite, you capture those stones. If in addition your opponent has stones opposite in the outer row then those are captured also.

Auto Moves. If your opponent has only one pit with two stones an auto-move will be made by the program, and the turn will come back to you.

Objective. To capture your opponent's stones. Game can be drawn by agreement.

Hex

Players aim to form a connection linking opposite sides of the board. Hex is known to be a deep strategical game that requires plenty of skill.

[ Hex on Wikipedia ]

JadeJack

This game was created by Barrie Evans. It is a game of territory, like Go, and played with disks that may stack. Unlike Go there is no capture, but the ownership of a stack of disks can change. The strengths that are exerted by occupied squares determine where moves may be made and if stacks of disks can be 'turned'. This is an advancement of the game of Hi-Jack that first appeared in issue 14 of the Abstract Games magazine [ www.abstractgames.org ].

The full rules are given at [ www.efbweb.uwclub.net ].

[ My JadeJack page ]

Board sizes are 9x9 and 10x10. To counter the first move advantage that the first player has the second player will be given a komi score of 1.5 points. The first move of the game may not be made in the centre. Games cannot end in a draw. The optional rule on scoring will not be used: players will not get an extra point for a 'jacked' stack. A game will end when a player can make no move. Passing of moves is allowed, and the game will end if two consecutive passes have been made. Because of the complication around strengths and scoring that might lead to miscalculation Gorrion will calculate the scores after each move and will also highlight the squares that are available to you.

Kauri

This is a seeding game of the Mancala and Bohnenspiel family. Six pits. Within each pit are six stones, five black and one white which is a special 'hammer' stone.

Seeding. In turn each player chooses a pit in their table that contains at least one white hammer stone, takes all the stones and seeds them anticlockwise, one by one, starting with the next pit. The hammer stones are seeded last. You skip your move whenever there is no hammer stone in any of the pits in your table. If there is only one valid move it will be auto-made by the program.

Capture. Captures are made as the stones are being seeded. If a hammer lands in an opponent pit that only has black stones then the stones there are captured and credited to your score. If a black stone lands in an opponent pit that contains only white hammers then the stone is captured and credited to your opponent. Hammer stones are never captured.

Objective. To get the greater score. Target is 31. Game is drawn if the scores are level, 30 each. The rule about continuing the play until one player can make no move will not be used.

Margo

Margo is played like Go but with marbles that can stack upwards. The following link gives the rules as followed by Gorrion.

Margo on this site is played with two variations. Under the 'standard' variation games are decided by marble count. Under this objective games will sometimes arrive at a position where the players need to spend many moves stacking marbles high inside their own territory in a race to be the last to fill in the liberties in their position. Under the alternative objective games are scored as in games of Go ( Japanese rules, prisoners + territory + komi ). Komi is 1.5 points to the player who goes second. There is no 'swap' option. Players may pass their turn.

[ Full rules for Margo ]

Merels ( Mill, Nine Men's Morris, Morabaraba )

Merels is known by many names and dates back at least to the time of the Roman Empire. Three variations are played on Gorrion.

9 Man ( standard version ). Take turns to place your pieces on the nodes of the grid. Thereafter slide them to an adjacent node. When you form a line of three ( a 'mill' ) you get to remove one of your opponent's pieces. But you may only remove one that forms part of a mill if there is no other piece free. You remove only one piece, even if you create several mills at the same time. You don't get a double, triple capture. If you have only three men left you may 'fly' your pieces to any vacant node. You win if your opponent can make no move or if he has only two men left. The game ends in a draw if the players both have three pieces and neither makes a capture within 10 moves.

10 Man ( Lasker proposal ). This variation was proposed by Emanuel Lasker, World Chess Champion between 1894 and 1921. 10 men each. There are no separate placement and movement stages. Players may slide a piece before all have been placed.

12 Man ( Morabaraba ). 12 men each. Four additional diagonals give more opportunities to form a mill. But note that with 12 pieces each and with 24 nodes on the board the players will need to try for at least one capture during the placement stage to avoid a positional deadlock.

[ Merels on Wikipedia ]

Onyx

This is a connection game. Like Hex both players aim to form a connection linking opposite sides of the board. It is played on a unique geometrical tessellation of triangles and squares where captures are allowed.

A recent game, created by Larry Back, it gives a new dimension to connection-oriented games and really deserves to be more widely known.

[ Full rules for Onyx ]

Othello ( Reversi )

This game is played on an 8x8 grid. Players aim to have the majority of disks in their colour at the end of the game. Disk colours are reversed as custodial entrapments are made.

Gorrion will automatically make a move if either player has only one valid move.

[ Full rules for Othello ]

Pente

Pente is a 5-in-a-row game played on a 19x19 board. Captures are allowed on 2-stone custodial configurations which ensure that achieving 5-in-a-row is never an easy task. There are many variations of Pente. The following link gives the rules as followed by Gorrion.

[ Full rules for Pente ]

Toguz Kumalak

'Toguz' or 'Togyz', 'Kumalak' or 'Korgool', there are different spellings for the same game. This is a seeding game of the Mancala and Bohnenspiel family. Each player starts with nine stones in each of nine trays.

Seeding. In turn each player chooses a tray in their table that contains stones, takes all the stones and seeds them anticlockwise, one by one. The first stone must be dropped into the tray which was just emptied. However, if there is only one stone it is put into the next tray.

Capture. If the last stone falls into a tray in the opponent's table, and this then contains an even number, the stones are captured, removed from the board and are added to the player's score.

Tuzdik. If the last stone falls into a tray in the opponent's table, and this then has three stones, the stones are removed from the board and are added to the player's score. The tray then becomes a 'Tuzdik' for the player. Then for the duration of the remaining game whenever a stone falls into this tray during seeding it is captured by its owner, removed and added to the owner's score. But there are restrictions on creating a Tuzdik. You may create only one during the game. The last tray in the opponent table ( ninth or rightmost ) cannot become a Tuzdik. A Tuzdik cannot be created if one has already been created in the same position in the opposite table.

Objective. To get a greater score than your opponent. The target is 82. Also if a player has no more stones in his table then the game ends. The remaining stones in the opponent's table are added to the opponent score.

Games may end in a draw by agreement.

 
Modified Rules for Gorrion. The above rules were standardised for play 'over the board'. The average game length under those rules is ~115 which is too high for online turn-based play. To make the game more suitable ( shorter and hopefully more exciting ) it is proposed to make some changes to the rules.

• The board starts with each player having a Tuzdik in the opponent's 1-position.
• 144 stones in total on the board. The target score is 73, a smaller number than under the standard rules.
• Multiple Tuzdiks can be created in your opponent's table and without any restrictions. The use of multiple Tuzdiks will ensure that the scores will increase more rapidly, especially towards the end of the game when opportunities for big captures are less frequent.

[ Toguz Korgool on Wikipedia ]
[ Togyz Kumalak on Wikipedia ]
[ Toguz Kumalak on mancala.fandom.com ]

Unlur

The game is an interesting connection game across a hexagonal board. Players aim to be the first to complete a chain of pieces that connects edges of the board. However the configurations that the players need to achieve are different. Black attempts to create a Y, a chain that connects three non-adjacent edges of the board while White attempts to create a line, a chain that connects opposite edges of the board. At the same time players need to avoid forming the connection pattern that their opponent is aiming for.

The colours are undecided at the start of the game. Initially both players play with the black pieces until one of the players decides that the pieces played are sufficient to counter the advantage that White has in aiming for the easier connection.

Invented by Jorge Gomez Arrausi, Unlur won the 2002 Unequal Forces Game Design Competition organised by the Abstract Games magazine.

[ Full rules for Unlur ]

Y

Players aim to be the first to complete a chain of pieces that connects all three edges of a triangular board. The variation that is supported is the curved or geodesic variation.

[ Full rules for Y ]