Editing Three-dimensional chess (section)

==Raumschach==
[[Ferdinand Maack]] (1861–1930) developed Raumschach (German for "Space chess") in 1907. He contended that for chess to be more like modern warfare, attack should be possible not only from a two-dimensional plane but also from above (aerial) and below (underwater). Maack's original formulation was for an 8×8×8 board, but after experimenting with smaller boards eventually settled on 5×5×5 as best. Other obvious differences from standard chess include two additional pawns per player, and a [[Fairy chess piece|special piece]] (two per player) called the [[List of fairy chess pieces#U|''unicorn'']].

===Board===
The Raumschach 3‑D&nbsp;board can be thought of as a cube sliced into five equal spaces across each of its three major coordinal planes. This sectioning yields a 5×5×5 (125&nbsp;cube) gamespace. The cubes (usually represented by squares and often called ''cells'') alternate in color in all three dimensions.

[[File:Raumschach gameboard.png|thumb|upright=1.0|left|Raumschach 5×5×5 gamespace]]

The horizontal levels are denoted by capital letters '''A''' through '''E'''.  Ranks and files of a level are denoted using [[Algebraic chess notation|algebraic notation]]. White starts on the '''A''' and '''B''' levels and Black starts on '''E''' and '''D'''. 

{{Raumschach diagram
 |tright
 |
 |rd|nd|kd|nd|rd
 |pd|pd|pd|pd|pd
 |  |  |  |  |
 |  |  |  |  |
 |  |  |  |  |
<!-- E -->
 |Ud|bd|qd|Ud|bd
 |pd|pd|pd|pd|pd
 |  |  |  |  |
 |  |  |  |  |
 |  |  |  |  |
<!-- D -->
 |  |  |  |  |
 |  |  |xo|  |xo
 |  |  |  |ox|
 |  |  |ox|oo|ox
 |  |  |  |  |
<!-- C -->
 |  |  |  |  |
 |  |  |  |  |
 |  |xo|ox|oo|ox
 |pl|pl|pl|pl|pl
 |bl|Ul|ql|bl|Ul
<!-- B -->
 |  |  |  |  |
 |  |  |  |  |
 |  |  |  |  |
 |pl|pl|pl|pl|pl
 |rl|nl|kl|nl|rl
<!-- A -->
 |Raumschach starting position.{{sfnp|Dickins|1971|p=17}} Unicorns are on Bb1, Be1, Da5, and Dd5. White's pawn on '''Bd2''' can move to cells with a white dot or capture on cells marked "<big>×</big>". Black's unicorn on '''Dd5''' can move to cells with a black dot or capture the white pawn on '''Aa2'''.
}}

===Rules===
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.
{{unordered list|style=list-style-position:inside 
 |A rook moves through the six ''faces'' of a cube in any rank, file, or column. 
 |A bishop moves through the twelve ''edges'' of a cube. 
 |A knight makes a [[Fairy chess piece#Leapers|(0,1,2) leap]] (the same effect as one step as a rook followed by one step as a bishop in the same outward direction) enabling it to control 24 different cells from the board's center. 
 |A unicorn moves in a manner unique to a 3D space: it moves through the ''corners'' of a cube (i.e. along a [[space diagonal]]), any number of steps in a straight line. Each unicorn can reach a total of 30 cells of the 125-cell gamespace; each player's pair can reach 60.
 |The queen combines the moves of a rook, bishop, and unicorn. The queen has a total of 26 different directions to move: 6 faces plus 12 edges plus 8 corners.
 |The king moves the same as the queen but one step at a time. 
 |A pawn, as in chess, moves and captures always forward toward the promotion rank (rank '''E5''' for White, rank '''A1''' for Black). This includes moving one step directly upward (for White) or downward (for Black), and capturing one step diagonally upward (White) or diagonally downward (Black), through a front or side cube ''edge''. In Raumschach there is no pawn initial [[Pawn (chess)#Placement and movement|two-step move]] (and consequently no capturing ''[[en passant]]''), and no [[castling]].
}}
{{Raumschach diagram
 |tleft
 |
 |  |  |  |  |
 |  |  |ox|  |
 |  |ox|  |ox|
 |  |  |ox|  |
 |  |  |  |  |
<!-- E -->
 |  |  |ox|  |
 |  |  |  |  |
 |ox|  |  |  |ox
 |  |  |  |  |
 |  |  |ox|  |
<!-- D -->
 |  |ox|  |ox|
 |ox|  |  |  |ox
 |  |  |nl|  |
 |ox|  |  |  |ox
 |  |ox|  |ox|
<!-- C -->
 |  |  |ox|  |
 |  |  |  |  |
 |ox|  |  |  |ox
 |  |  |  |  |
 |  |  |ox|  |
<!-- B -->
 |  |  |  |  |
 |  |  |ox|  |
 |  |ox|  |ox|
 |  |  |ox|  |
 |  |  |  |  |
<!-- A -->
 |White's knight on '''Cc3''' can move or capture on cells marked "<big>×</big>".
}}
{{-}}