Pieces have the same movement rules as normal chess. A knight for instance moves 3 spaces along one axis, and 1 space along another axis. If you time travel you

Pieces have the same movement rules as normal chess. A knight for instance moves 3 spaces along one axis, and 1 space along another axis. If you time travel you're essentially sacrificing one of those spatial moves for a temporal move. For example 2 spaces back in time and 1 forward. So while it's not entirely giving up a move it's fairly close, especially for pieces that only move along a single axis at a time.