- Art Deco
- In physical tournaments, the IRF requires Art Deco to be the style of chess pieces, because this artistic movement was in the 1920s—1930s; Art Deco is period appropriate.
- battery
- A battery is a formation where two or more chess pieces line up to apply coordinated pressure on a target, often a pinned piece.
- bishop
- A Bishop is a chess piece that moves any distance through the edges of a cube. For more information, see the Tutorial.
- blitz
- A blitz game is an informal and unrated game with a short time-control, used as a tie-breaker. For more information, see Charter (§ VII).
- boardmate
- Boardmate occurs when the King is in check and mated on its current level, but may flee to an adjacent level. In Raumschach, boardmate is a spatially incomplete checkmate.
- castling
- In traditional chess, castling is a special move in which the King moves two squares toward a Rook, and then that Rook moves to the square the King crossed over. Castling is not allowed in Raumschach.
- check
- A King in check is under immediate attack and could be captured on the subsequent move of the opponent if nothing is done to stop it. The player whose King is in check must make a move that removes the check. A King in check is not necessarily in spacemate.
- checkmate
- The term “checkmate” is from flat chess. In some literature of Raumschach, this term is replaced with boardmate and spacemate as more explicit terms, and in other literature of Raumschach, checkmate is used. The IRF uses boardmate and spacemate rather than checkmate. In flat chess, checkmate occurs when the King is in check and mated; the game is over.
- chess
- Chess is a family of two-player, turn-based, perfect-information strategy games using a shared, finite board and a fixed set of unit-type pieces, whose patterns of movement and capture are codified and whose goal is to eliminate or constrain the opponent’s key unit (typically a king).
- classical
- A classical game is a game with the longest formal time-control via a chess clock. For more information, see Charter (§ VII).
- corners
- The corners of a cube (or a cell) are the intersections of three faces. Each cube has 8 corners. In Raumschach, a Unicorn moves any distance through the corners of a cube, thus triagonally. Movement through corners is purely three-dimensional movement, changing simultaneously the level, file, and rank. Thus, a Unicorn can never move on the same level, the same file, or the same rank.
- correspondence play
- Correspondence games are conducted by e-mail or through any agreed asynchronous medium, using IRF Standard Notation. For more information, see Charter (§ VIII).
- division
- The IRF has Division 1 (by invitation only, and invitations are based on the IRF rating of the player) and Division 2 (which excludes players in Division 1). Divisions 1 and 2 are further subdivided for human-only (Divisions 1A and 2A) and inhuman-only (1B and 2B). For more information, see Charter (§ VII).
- draw
- A game is drawn by stalemate, mutual agreement, threefold repetition, the fifty move rule, or the seventy-five move rule. For more information, see the Charter (§ IV).
- edges
- The edges of a cube (or a cell) are the intersections of two faces. Each cube has 12 edges. In Raumschach, a Bishop moves any distance through the edges of a cube, thus diagonally on the same level, or in the style of walking up or down a staircase when moving through an upper or lower edge. Movement through edges is two-dimensional movement, always changing two-of-three axes, such as file and rank, level and file, or level and rank.
- EloR
- EloR is a custom form of Elo by the IRF for Raumschach. It is a method of rating players. For more information, see Charter (§ IX).
- en passant
- In traditional chess, en passant is a special Pawn capture rule, allowing a Pawn to capture an opponent’s Pawn that has just advanced two squares from its starting position. The capturing Pawn moves diagonally to the square the enemy Pawn passed over, removing it from the board.
In Raumschach, Pawns are not allowed to move two squares on their first move, and so en passant does not apply to Raumschach.
- engine
- An engine in Raumschach is an AI opponent. For more information, see Raumschach Engines.
- faces
- The faces of a cube (or a cell) are its flat surfaces. For example, a traditional die has six faces, each marked with pips. In Raumschach, a Rook moves any distance through the faces of a cube, such as forward or backward, left or right, or up or down. Movement through faces is one-dimensional movement, always changing only one-of-three axes, such as the level, file, or rank.
- fairy chess
- Fairy chess refers to chess variants and problems that modify standard rules, such as introducing new pieces with unique movements, altered boards, or special conditions for capturing and checkmate. The term “fairy chess” was coined by Henry Tate in 1914 to describe these imaginative, non-standard chess forms. Thomas Raynor Dawson (1889–1951), known as the “father of fairy chess,” greatly expanded the field.
- figurine algebraic notation
- Dr. Ferdinand Maack used algebraic notation, and the IRF has internationalized the symbols of the chess pieces to be figurines, HTML symbols, with the exception of the Unicorn (U). For more information, see Charter (§ VI).
- file
- A file is a column on a level. When one player sits in front of the physical set and the other player sits behind it, the file extends between the players. In “Normal Form” there are 5 files: a–e.
- flat chess
- Flat chess refers to bidimensional chess.
- fork
- A fork is a tactic in which one chess piece attacks simultaneously two or more opponent pieces.
- Giraffe
- The Giraffe is an additional chess piece that is used in the 7×7×7 or seven-board form of Raumschach. Each move consists of one leap like a Knight followed by one step farther like a Unicorn.
- Großraumschachmeister (GRSM)
- A Großraumschachmeister (GRSM) is a member with a sustained rating of 2,400 or above in Raumschach.
- Inhuman
- Inhuman-only players are allowed in Divisions 1B and 2B. An inhuman player is an AI engine or a Large Language Model (LLM).
- king
- A King is a chess piece that moves as a Queen, but takes only one step. For more information, see the Tutorial.
- knight
- A Knight is a chess piece that moves as in an L-shape, two steps in one direction and one step in an orthogonal direction. For more information, see the Tutorial. However, in SIII4 the usual rule adopted is that the L-shape movement is limited to the same level, and movement between levels is like a Unicorn.
- level
- Raumschach has multiple levels (or boards or planes). The “Normal Form” of Raumschach has five levels, labeled from bottom to top as A, B, C, D, and E. Previous variants were labeled instead with lower-case Greek letters, such as α, β, γ, δ, and so on, up to the number of levels in the variant.
- live remote play
- Live Remote Play is synchronous play conducted via a video communication platform (such as Signal) where both players are mutually visible and audible for the duration of the game, simulating the conditions of over-the-board tournament play. For more information, see Charter (§ VIII).
- Maackesgeist
- Maackesgeist is the name of an engine that was replaced by Raumfischer. For more information, see Maackesgeist.
- match play
- A match play is a bilateral match between exactly two players, such as in the world championship. For more information, see Charter (§ VII).
- Normal Form
- The “Normal Form” of Raumschach refers to the final and mature form of Raumschach, which is one form of 5×5×5 or five-board Raumschach.
- pawn
- A Pawn is a chess piece that moves in one step forward-only like a Rook toward its promotion rank (also including upward for White or downward for Black), and captures in one step through an edge of a cube like a Bishop. In the “Normal Form,” a Pawn has up to 2 possible moves or 5 possible captures. For more information, see the Tutorial. Variants use other rules.
- promotion
- A Pawn is promoted when it reaches its “promotion rank,” which is a combination of level and rank in Raumschach. In “Normal Form”, a White Pawn is promoted when it reaches level E and rank 5, and a Black Pawn is promoted when it reaches level A and rank 1. When a pawn promotes, that pawn is replaced with another piece of the same color, selected by the player. The replacement is either a Rook, Bishop, Unicorn, Queen, or Knight. Most commonly, a Pawn is replaced with a Queen.
- queen
- A Queen is a chess piece that moves as a Rook, Bishop, or Unicorn. For more information, see the Tutorial.
- rank
- A rank is a row on a level. When one player sits in front of the physical set and the other player sits behind it, each rank extends toward the left and right of each player. In “Normal Form” there are 5 ranks: 1–5. Rank 1 is closest to the White player, and Rank 5 is closest to the Black player.
- rapid
- A rapid game is a game with a time-control via a chess clock, and it is between a classical game (which is longer) and a blitz game (which is shorter). For more information, see Charter (§ VII).
- Raumfischer
- Raumfischer is the name of an heuristic-based engine that was designed to play Raumschach in the style of Bobby Fischer, even though Bobby Fischer never played Raumschach. For more information, see Raumfischer.
- Raumschach
- Raumschach (German: “Space Chess”) is the first extant game of three-dimensional chess.
- Raumschachmeister (RSM)
- A Raumschachmeister (RSM) is a member with a sustained rating of 2,200 or above in Raumschach.
- Raumschach Game Notation (RGN)
- Raumschach has, here, its own game notation. For more information, see Charter (§ VI) and RGN.
- rook
- A Rook is a chess piece that moves any distance through the faces of a cube. For more information, see the Tutorial.
- round robin
- A round robin is a tournament event by the IRF in which every participant plays every other participant exactly once. For more information, see Charter (§ VII).
- SIII notation
- Dr. Ferdinand Maack used SIII notation to distinguish between different forms of Raumschach. He described his variants, typically, as SIII5 A, where “S” was short for “schach” (chess), the numerator “III” meant three-dimensions, the denominator indicated the space (such as 5 means 5 squares per board), and lastly “A” (or “B” or “C”) indicated a particular version. So, SIII5 A means version A of three-dimensional chess on boards with 5 spaces.
- skewer
- A skewer is a tactical pattern in which an attacker has a straight line on a more valuable chess piece, with a less valuable piece behind it. The defender saves the more valuable piece by moving it, which exposes the less valuable piece to be captured.
- space chess
- See Raumschach.
- spacemate
- Spacemate occurs when the King is in check and mated on its current level, and cannot flee to an adjacent level; the game is over. Spacemate is a three-dimensional checkmate.
- stalemate
- Stalemate occurs when there are no legal moves for any piece and the King is not in check; the game is drawn.
- Swiss system
- The Swiss System is designed for events with too many players for a full round robin, or where the time available permits only a limited number of rounds. No player is eliminated; all players compete in every round. For more information, see Charter (§ VII).
- unicorn
- A Unicorn is an additional chess piece for the SIII5 (or 5×5×5 or five-board) form of Raumschach. A Unicorn moves any distance through the corners of a cube; it moves triagonally through vertices, always in three dimensions at once. Out of 125 cells, each Unicorn can reach only 30 cells. For more information, see the Tutorial.
From Be1 or Da5, a Unicorn can reach these 30 cells: Ab2, Ab4, Ad2, Ad4, Ba1, Ba3, Ba5, Bc1, Bc3, Bc5, Be1, Be3, Be5, Cb2, Cb4, Cd2, Cd4, Da1, Da3, Da5, Dc1, Dc3, Dc5, De1, De3, De5, Eb2, Eb4, Ed2, Ed4.
From Bb1 or Dd5, a Unicorn can reach these 30 cells: Aa2, Aa4, Ac2, Ac4, Ae2, Ae4, Bb1, Bb3, Bb5, Bd1, Bd3, Bd5, Ca2, Ca4, Cc2, Cc4, Ce2, Ce4, Db1, Db3, Db5, Dd1, Dd3, Dd5, Ea2, Ea4, Ec2, Ec4, Ee2, Ee4.
- world championship
- The annual IRF world championship determines the world champion in Raumschach. For more information, see Charter (§ VII).