strategy
Strategy (from Greek στρατηγία ''stratēgia'', "art of troop leader; office of general, command, generalship") is a general plan to achieve one or more long-term or overall goals under conditions of uncertainty. In the sense of the "art ...
board game
Board games are tabletop games that typically use . These pieces are moved or placed on a pre-marked board (playing surface) and often include elements of table, card, role-playing, and miniatures games as well.
Many board games feature a comp ...
, an early entrant in the 1960s
3M bookshelf game series
The 3M bookshelf game series is a set of strategy and economic games published in the 1960s and early 1970s by 3M Corporation. The games were packaged in leatherette-look large hardback book size boxes in contrast to the prevalent wide, flat ga ...
. It became one of the most popular and enduring games in the series. It is a
connection game
A connection game is a type of abstract strategy game in which players attempt to complete a specific type of connection with their pieces. This could involve forming a path between two or more endpoints, completing a closed loop, or connecting all ...
where players alternate turns placing pegs and links on a pegboard in an attempt to link their opposite sides. While TwixT itself is simple, the game also requires strategy, so young children can play it, but it also appeals to adults. The game has been discontinued except in Germany and Japan.
History
TwixT was invented as a paper and pencil game in 1957 by
Alex Randolph
Alexander Randolph (4 May 1922 – 27 April 2004) was a Bohemian-American designer of board games and writer. Randolph's game creations include ''TwixT'', '' Breakthru'', '' Hol's der Geier'', '' Inkognito'' (with Leo Colovini), ''Raj'', ''Ri ...
, a game designer. When Alex was commissioned along with Sid Sackson by 3M in 1961 to start a games division, the game was issued as a boardgame, one of the first 3M bookshelf games.
Avalon Hill
Avalon Hill Games Inc. is a game company that publishes wargames and strategic board games. It has also published miniature wargaming rules, role-playing games and sports simulations. It is a subsidiary of Hasbro, and operates under the company' ...
took over publication in 1976 when 3M sold its game division. Avalon's parent company was acquired by
Hasbro
Hasbro, Inc. (; a syllabic abbreviation of its original name, Hassenfeld Brothers) is an American multinational conglomerate holding company incorporated and headquartered in Pawtucket, Rhode Island. Hasbro owns the trademarks and products of ...
in 1998, and the game was discontinued. The game is no longer produced in the United States, but a succession of German companies has produced the game since the 1970s under license from Avalon. TwixT was short-listed for the first
Spiel des Jahres
The Spiel des Jahres (, ''Game of the Year'') is an award for board and card games, created in 1978 with the purpose of rewarding family-friendly game design, and promoting excellent games in the German market. It is thought that the existence ...
Twixt is played on a board comprising a 24×24 square grid of holes (minus 4 corner holes). The game has two types of playing pieces, pegs, which fit into the holes, and links, which fit into the top of the peg pieces and are used to connect to peg pieces. In the 3M edition, players are Red and Black; different sets may use different colors. The topmost and bottommost rows of holes belong to the lighter color; the leftmost and rightmost rows to the darker color.
*The players take turns placing pegs of their respective colors on the board, one peg per turn.
*The player with the lighter color makes the first move.
*A player may ''not'' place a peg on their opponent's border rows.
*To counteract first-move advantage, the
pie rule
The pie rule, sometimes referred to as the swap rule, is a rule used to balance abstract strategy games where a first-move advantage has been demonstrated. After the first move is made in a game that uses the pie rule, the second player must sel ...
is suggested. After the first peg is placed, the second player has the option to swap sides. This is typically indicated by turning the pieces box end for end, or swapping boxes if they are separate. If the second player chooses not to swap immediately after the first peg is placed, then sides may not be swapped later in that game. (This "one-move equalization" was added by Randolph after 3M published his game. It is present in the Schmidt Spiele edition and all later editions.)
*After placing a peg, a player may ''link'' one or more pairs of pegs on the board of their colour. The links can only connect two pegs a knight's move away from each other, and cannot cross another link; they block other links, most importantly those of the opponent. As part of the player's move, they may remove their own links (but not those of the opponent) in order to rearrange the sequence of links on the board. A variant for pencil and paper play allows a connection to cross the player's links but not those of the opponent.
*The object is to make a continuous chain of linked pegs connecting the player's border rows. If neither player can achieve this, the game is a draw.
Computational complexity for general rectangular boards
TwixT has been proven to be
PSPACE-complete In computational complexity theory, a decision problem is PSPACE-complete if it can be solved using an amount of memory that is polynomial in the input length (polynomial space) and if every other problem that can be solved in polynomial space can b ...
for determining the game value, via a reduction from Hex. TwixT has also been shown to be
NP-complete
In computational complexity theory, a problem is NP-complete when:
# it is a problem for which the correctness of each solution can be verified quickly (namely, in polynomial time) and a brute-force search algorithm can find a solution by tryi ...
regarding whether a single set of vertices can support a connecting path, via a reduction from 3-satisfiability.
These proofs are indicative of a complex strategy: the game has not been solved, no winning strategy has been discovered, nor is the outcome of the game with
perfect play
A solved game is a game whose outcome (win, lose or draw) can be correctly predicted from any position, assuming that both players play perfectly.
This concept is usually applied to abstract strategy games, and especially to games with full informa ...
known.
Related games
On the 24×24 grid, tactical considerations tend to predominate. The opening phase is over quickly, and the rest of the game is spent attempting to tactically execute the plan. Hex, which has a very similar game object, may have more predictable tactics, but strategical considerations are much more important. In this sense, Hex is more like Go than TwixT, since a single move is generally less committal, and consequences may take longer to play out.
Variants
One variant is Twixt PP (Paper and Pencil). The rules are almost identical to standard TwixT, except links are never removed and a player's ''own'' links are allowed to cross each other. A winning path might loop across itself but crossed links are not connected to each other at the intersection. The paper and pencil rules may reduce the number of draws (which are already rare). Whether it reduces the complexity of the game or not is highly debatable.
This rules difference has no effect in terms of game outcome most of the time. For those rare situations where it does, most of those cases are where a draw under standard rules is a decisive game under PP rules.
Row handicapping can be used to equalize the game for players of different strengths. The simplest handicap is to allow the weaker player to move first (i.e. eliminate the pie rule). Beyond that, one dimension of the grid is reduced so the weaker player has a shorter distance to span.
The game may be played on different size grids. The 12×12 board shown here leads to a very short game. On the standard board, tactics dominate; larger boards introduce deeper strategic considerations. Since most commercial sets use boards which are made from four "quadrants" which either clip together or are hinged, a 36×36 grid could be assembled from three standard sets of the same size. In Europe, there briefly appeared a TwixT knock-off called "Imuri" which used a 30×30 grid. The board had no holes, and lines were drawn to indicate where the links could be placed. This edition was removed from shelves for copyright infringement.
Mark Thompson's variant Diagonal TwixT has the same rules as standard TwixT, but the border lines run at a 45-degree angle to the grid. David Bush's version has the border lines running parallel to link paths. These variants result in different tactical patterns.
Competition
The official world championships were held as part of the
Mind Sports Olympiad
The Mind Sports Olympiad (MSO) is an annual international multi-disciplined competition and festival for games of mental skill and mind sports. The inaugural event was held in 1997 in London with £100,000 prize fund''Mind Sports Olympiad Supp ...
in 1997, 1998 and 1999. Since 2000 TwixT has had a major international tournament as part of the MSO but there has been no official World Championships. Since 2011, the TwixT event at the MSO has again become the World Championships. The list of winners is given below.
List of MSO champions
Reviews
*1980 Games 100 in ''
Games
A game is a structured form of play, usually undertaken for entertainment or fun, and sometimes used as an educational tool. Many games are also considered to be work (such as professional players of spectator sports or games) or art (such ...