What is Sofia Rules?

Sofia Rules refers to a specific set of rules used in some chess tournaments to discourage short or prearranged draws. Under Sofia Rules, players are not allowed to agree to a draw during the first 30 moves of a game unless there are unavoidable circumstances like perpetual check, threefold repetition, or a completely symmetrical position, and these draws must be approved by the tournament arbiter. Named after Sofia, Bulgaria, where these rules were first applied in a significant tournament, M-Tel Masters.