A game played with a deck of 42 cards of 21 different kinds, all in the same suit. 12 of the cards are numbered, the rest are named cards with special abilities. Each player is dealt one card. Going round the table a player can choose to swap his card with the player to his left, but some cards have special abilities and will 'kill off' e.g. the player wishing to swap. The object of the game is to be the last remaining player, and thereby winning the pot.
According to the history section of an Offason edition, this game was very popular in Sweden starting from the 1750's and about a hundred years thereafter. While a part of the Swedish cultural tradition, it is in fact based on a popular 17th century Italian version ("Cuccú") of a medieval French 'hazard' game ("Coucou"); both of these names refer to the cuckoo, which is the highest card in the deck.
Kille can be played in the original form as 'single-card kille' or as the 'five-card kille' variant developed in the mid-19th century.