Maximummer

Maximummer is a condition that restricts move choice. Unless a color is stated, it applies to Black: on every turn Black must play one of the geometrically longest legal moves available. If several legal moves tie for maximum length, any of them may be chosen.

Length is the straight-line distance between the centers of the starting and ending squares, not the number of crossed squares or the move's tactical strength. A knight move has length square root of five. In castling, the special move in which the king and a rook move together, their two displacements are added: kingside, or short, castling measures four units, while queenside, or long, castling measures five.

The word legal retains ordinary check rules. A king in check must escape, and length is compared only among legal replies. An attack on the king is still check even if capturing that king would not be the longest move.

A Double Maximummer applies the obligation to both sides. The rules may also state explicitly that it applies to White alone. The condition can be combined with unorthodox goals such as the reflexmate, but it does not by itself change the problem's goal.