What is the number of possible chess moves in a chess game?

== == There are 20 possible opening moves in Chess. There are eight pawns and each pawn has two possible moves. There are two knights and each knight has two possible moves. e4 King's pawn opening (B00) d4 Queen's pawn (A40) c4 English opening (A10) Nf3 Reti opening (A04) f4 Bird's opening (A02) b3 Nimzovich-Larsen attack (A01) Na3 Durkin's attack (A00) h4 Anti-Borg (Desprez) opening (A00) f3 Gedult's opening (A00) E3 Van't Kruijs opening (A00) d3 Mieses opening (A00) c3 Saragossa opening (A00) a4 Ware (Meadow Hay) opening (A00) a3 Anderssen's opening (A00) Nc3 Dunst (Sleipner, Heinrichsen) opening (A00) Nh3 Amar (Paris) opening (A00) h3 Clemenz (Mead's, Basman's or de Klerk's) opening (A00) g4 Grob's attack (A00) g3 Benko's opening (A00) b4 Polish (Sokolsky) opening (A00)