Bughouse chess when captured. In play over the board, a promoted pawn can be put on its side to indicate promotion. A pawn placed on the second rank may move two squares on its first move. Each player must keep the reserve or stock pieces on the table in front of the board, always visible to all players of the game. Bughouse chess is usually played with chess clocks to prevent players from waiting indefinitely for a piece. Clocks are placed on the outside so that each player can see both clocks. At the start of the game, the players with the
Three-dimensional chess by squares and often called "cells") alternate in color in all three dimensions. The horizontal levels are denoted by capital letters A through E. Ranks and files of a level are denoted using algebraic notation. White starts on the A and B levels and Black starts on E and D. White moves first. The game objective, as in standard chess, is checkmate. Rooks, bishops, and knights move as they do in chess in any given plane. Probably the most familiar 3D chess variant to the general public is the game of Tri-Dimensional Chess (or Tri-D Chess), which can be seen