A ply is half a move. Or to put it another way, one move is one ply by white and one ply by black. This is a term that is common to all sequential games. http

A ply is half a move. Or to put it another way, one move is one ply by white and one ply by black. This is a term that is common to all sequential games. https://en.wikipedia.org/wiki/Ply_(game_theory) https://en.wikipedia.org/wiki/Ply_(game_theory)