Acol is a bridge bidding system. It is the name of a road in Hampstead, London, where there was a bridge club in which the system started to evolve in the 1930s. It was popularised in Britain by Iain Macleod in his book "Bridge is an Easy Game", published in 1952. The Acol system is continually evolving but the underlying principle is to keep the bidding as natural as possible. It is common in the British Commonwealth but rarely played in America.
A chess variant is any game derived from or related to chess. In practice, a specific chess variant may be similar to chess or radically different. The broad definition of chess variants is so universal, it may include nearly any abstract battle or war game played upon a board.
