Knightmare Chess adds a whole new element of unpredictability to the static game of standard Chess by giving players cards that they can play before, after, or sometimes instead of their turns. Some cards affect only a single move, while others change the entire game. Multiple variants are included in the rules.

The 2014 edition of Knightmare Chess includes the cards from both Knightmare Chess and Knightmare Chess 2 — 158 cards in all.