Because of the forced capture rule, losing chess games often involve long sequences of captures by one player. This means that a minor mistake can doom a game. Such mistakes can be made from the very first move—losing openings for White include 1.a3, 1.b4, 1.c3, 1.d3, 1.d4, 1.e4, 1.f3, 1.f4, 1.h3, 1.h4, 1.Na3, 1.Nc3, and 1.Nf3. Some of these openings took months of computer time to solve, but wins against 1.e4, 1.d4, and 1.d3 consist of simple series of forced captures and can be played from memory by most average players. The other openings: 1.a3, 1.b4, 1.c3, 1.f3, 1.f4, 1.h3, 1.h4, 1.Na3, 1.Nc3, 1.Nf3 can be solved by very skilled and experienced players.