Abstract: A golf putter having a forward wall forming a putting face, a portion of reduced thickness behind the wall, a slot in the rear portion of the wall perpendicular to the putting surface, a cavity having a portion underlying the slot, and an exposed portion rearwardly of the wall occupying a major portion of the vertical dimension of the putter and having a marker line spaced downwardly from the upper surface of the slot and visible through the slot to form an alignment sight.