Kal-toh is a Vulcan game of recreation which can be played alone or with multiple individuals.
It is considered a game of deep strategy with the objective being to use the playing rods known as t'an to change the shape of the Kal-toh set into a more ordered form. The placement of each rod alters the shape of all the other pieces which can either lead it into a more 'harmonius' shape or result it into being even more chaotic in appearance. The victor is the person who manages to transform the shape into an ordered form.
Some have compared the game to chess, however, Kal-toh is as different from chess as chess is towards tic-tac-toe. Seven of Nine claimed that the usage of elementary spatial harmonics can result in victory in the game, as demonstrated by herself when she won a game against Tuvok and Harry Kim.
Lieutenant Commander Tuvok of the USS Voyager stated that Kal-toh: "Is not about striving for balance but about finding the seeds of order even in the midst of profound chaos." (VOY episodes: "Alter Ego", "Darkling", "The Omega Directive", "Endgame")
In 2376, a new variation of kal-toh was available to buy on Deep Space 9's Promenade. Shathrissia zh'Cheen considered purchasing it as a gift for Thavanichent th'Dani. Thriss compared the game to chess. (DS9 novel: This Gray Spirit)