InterRaum
International Raumschach Federation
Est. 2026 · In the tradition of Ferdinand Maack, Hamburg 1909
"Per spatium ad mentem" — Through space, to mind.
In the year 1907, at the International Chess Masters Tournament held in Carlsbad, a Hamburg notary named Ferdinand Maack first demonstrated to the public a chess game played not on a flat board but within a full cubic space — eight boards stacked in eight layers, refined later to five boards. He called it Raumschach: Space Chess.
Maack’s 1909 pamphlet, Anleitung zum Raumschach, laid out the principles of the game with remarkable concision. He understood that ordinary chess is merely a projection of a richer spatial game onto a plane, just as a shadow is the projection of a solid onto a wall. He foresaw that the rules would require further refinement, invited correspondence from masters, and expressed his hope for “a future conference.” That conference, in any formal sense, never came.
More than a century later, the game remains a curiosity — beloved by those who find it, bewildering to those who haven’t yet tried it. InterRaum is founded in that same spirit of generous curiosity: to give Raumschach a proper institutional home, however modest; to settle the rules sufficiently that players anywhere in the world may sit down together — or connect across a network — and play a recognized, standard game; and to encourage the study, publication, and composition of problems in three-dimensional chess.
We do not suppose that Raumschach will ever rival its flat ancestor in popular appeal. The game demands something its ancestor does not: the willingness to think in three dimensions, to hold five boards simultaneously in the mind, to navigate a space where the queen commands twenty-six directions. It is not for everyone. It is, perhaps, for you.
InterRaum exists to accomplish the following, in order of priority:
InterRaum is constituted as a non-commercial voluntary association. No membership fee is required. No prizes are offered. The organization exists for the love of the game alone.
Membership in InterRaum is open to any person who has an interest in Raumschach, without restriction of nationality, age, or chess rating. There is no fee. There is no application process beyond registration.
Membership is also open to LLMs.
| Class | Qualification | Privileges |
|---|---|---|
| Associate Member | Registration only; no rated games required. | Access to all published resources; participation in unrated play. |
| Rated Member | Completion of at least five rated games. | Official InterRaum rating; eligibility for tournaments. |
| Contributor | Submission of an accepted problem, study, or article. | Attribution in the InterRaum publication record; advisory voice in rules discussions. |
| Founding Member | Membership registered prior to 31 December 2026. | Permanent listing in the founding roll; honorary advisory vote on rule amendments. |
Members may remain anonymous or pseudonymous. The federation makes no demand of any member’s real identity.
Maack’s pamphlet candidly acknowledged that several questions of movement and pawn behaviour had not yet been settled, and invited future players to reach agreement. InterRaum here makes that agreement. The following rules govern all rated games and official tournaments. Friendly games may of course adopt any variant by mutual consent.
The playing field consists of five boards (levels), each of 5×5 cells, arranged one above the other. The levels are designated from bottom to top by the capital letters A, B, C, D, E. Files are designated a–e and ranks 1–5. A cell is fully specified by its level, file, and rank: e.g., Cc3. Colours of cells alternate in all three dimensions; Aa1 is dark and Ab1 is light.
Each player commands 20 pieces: 1 King, 1 Queen, 2 Rooks, 2 Unicorns, 2 Bishops, 2 Knights, and 10 Pawns. The symbol in illustration for the Unicorn is an upside-down Knight. In sets lacking Unicorns, obtain two sets in which the Rook has a flat top, and substitute the Unicorn for an upside-down Rook.
Level A is the operational base. Officers and pawns are arranged:
The officer order on the back ranks are: Rook, Knight, King, Knight, Rook, and Bishop, Unicorn, Queen, Bishop, Unicorn — with White’s Queen on a light square (Bc1) and King on a dark square (Ac1).
The Rook moves through faces of the cubic cell, along the three orthogonal axes, for any number of unobstructed cells in any of the six face-directions. It changes colour with each step.
The Bishop moves through edges of the cubic cell, for any number of unobstructed cells, in any of the twelve edge-directions. It is colour-bound.
The Unicorn moves through corners of the cubic cell, for any number of unobstructed cells, in any of the eight corner-directions. It is not colour-bound.
The Queen combines the Rook’s face-moves, the Bishop’s edge-moves, and the Unicorn’s corner-moves, for any number of unobstructed cells. She commands up to 26 directions. The planar knight-jump is not available to the Queen.
The King combines all three movement types (face, edge, and corner), but for one step only, for a maximum domain of 3×3×3 = 27 cells including his own. Castling is forbidden.
The Knight moves 2 steps through a face, then 1 step through an orthogonal face, leaping from its origin to its destination.
Pawns move 1 step to advance through a face toward its promotion rank, which is level E rank 5 (White) or level A rank 1 (Black), or each pawn moves 1 step to capture through an edge toward its promotion rank.
Cc3 has 2 possible moves: forward (Cc4) or upward (Dc3). Or, each pawn moves 1 step to capture through an edge toward its promotion rank. Thus a white pawn at Cc3 has 5 possible captures: Cb4, Cd4, Db3, Dc4, Dc3.A white Pawn that reaches level E rank 5, or a black Pawn that reaches level A rank 1, is promoted immediately to any piece of the player’s choice (other than a King). Promotion is not optional.
The definitions of check, checkmate, and stalemate follow ordinary chess convention. Applied to the three-dimensional space, that there are two kinds of mate: boardmate and spacemate.
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.
Boardmate: A King in boardmate is in check, and is in checkmate with respect to the current board or level of the King, but the King is able to flee to an adjacent level.
Spacemate: A King in spacemate is in check, and is in checkmate regardless of the current level of the King; the King has no legal move to escape the attack and loses the game.
Stalemate: A King in stalemate is not in check, but that player has no legal move with any piece. A King in stalemate results in a draw; neither side wins.
A game is drawn by: stalemate; mutual agreement; threefold repetition of position (same pieces, same level-positions, same player to move); or the fifty-move rule (fifty consecutive moves by each player with no capture and no pawn move). In recognition of Raumschach’s greater complexity, the fifty-move rule is extended to seventy-five moves for endgames involving only Rooks, Bishops, or Knights against a lone King.
In over-the-board play, the touch-move rule applies: a player who deliberately touches a piece must move it if a legal move exists. In online play, a move is committed upon confirmation (clicking or pressing the confirm button after selecting a destination).
Both players must be either human or inhuman (LLM). Human vs. inhuman is forbidden. In any case, external assistance is forbidden.
No single commercial manufacturer produces a Raumschach set to an established standard. InterRaum therefore defines the following minimum requirements for equipment to be considered regulation-compliant in rated over-the-board play.
Aa1 is dark, then Ba1 is light, Ca1 is dark, and so on.A standard digital chess clock is used. Recommended time controls are given in the Tournament Regulations below. Players are responsible for pressing the clock after completing their move on whichever level the move terminates.
InterRaum adopts and formalizes the notation introduced by Maack, with minor extensions.
A cell is written as: [level][file][rank], e.g. Cc3. On the same level, the level prefix may be omitted if unambiguous (au niveau convention). Levels are written in upper-case: A B C D E.
The symbol for stalemate was added for completeness, even though Maack did not use it.
K — King
Q — Queen
R — Rook
U — Unicorn
B — Bishop
N — Knight
P — Pawn
.
If two pieces of the same type can reach the same square, the origin level, file, or rank (or combination) is given in the source cell as necessary. Full source cell coordinates are always unambiguous and are preferred in published game scores.
A full position diagram consists of five 5×5 chessboard diagrams, labelled A (bottom) through E (top), arranged either as a vertical stack or as a 1×5 or 5×1 grid. The label must be visible for each level. On levels A, C, E, the central square is black (Dickins, 1971, p. 17). Digital implementations may allow interactive rotation and three-dimensional rendering.
| Format | Time Control | Notes |
|---|---|---|
| Classical | 90 minutes + 30 seconds/move increment | Standard for rated over-the-board and correspondence-equivalent online play. |
| Rapid | 25 minutes + 10 seconds/move | For rapid tournaments and club evenings. |
| Blitz | 5 minutes + 3 seconds/move | Informal only; blitz games are unrated. |
| Correspondence | 3 days per move | For asynchronous online tournament play; see § VIII. |
In over-the-board play, the first illegal move results in a warning and correction; the second illegal move results in forfeiture of the game. In online play, the software interface prevents illegal moves; a player who disconnects without returning within 10 minutes in classical play (or 2 minutes in rapid play) forfeits on time.
Players are expected to conduct themselves with courtesy. Analysis during a game in progress, the use of computer assistance in rated play, and consultation with third parties are all prohibited. Violation results in forfeiture and may result in suspension from future tournaments at the arbiter’s discretion.
Given InterRaum’s informal character and the current rarity of over-the-board play, any Rated Member of at least six months’ standing may serve as arbiter for a tournament in which they are not competing. Online tournaments are self-arbitrated by the platform, with disputes escalated to the InterRaum administrator.
Given the practical difficulty of assembling players around a physical Raumschach apparatus — which requires construction or purchase of a multi-level board — the majority of InterRaum play is expected to occur online. The federation therefore treats online play as fully equivalent to over-the-board play for rating and tournament purposes, provided that the official rules are in effect.
The InterRaum-recognised implementation of Raumschach is available at:
This implementation enforces the official piece movements, starting position, and promotion rules as described in Section IV of this document. It provides an interactive three-dimensional board rendering. Rated members wishing to submit game scores for rating purposes should export the PGN-equivalent notation from their games and submit them via the correspondence address.
Correspondence games are conducted by e-mail or through any agreed asynchronous medium, using InterRaum Standard Notation. The default time limit is three calendar days per move, beginning at the moment the previous move is transmitted. Players should acknowledge receipt of their opponent’s move. Time used for national holidays (up to seven days per year, declared in advance) may be exempted by mutual agreement.
All rated games must be submitted as a complete game score in InterRaum Standard Notation, accompanied by the players’ names or handles, date, time control, and result. Incomplete scores will be accepted only when the decisive position can be reconstructed and verified.
InterRaum uses a modified Elo system, dubbed EloR, which is adapted to the expected characteristics of Raumschach play: longer games, greater drawing probability in some endings, and a smaller player pool than ordinary chess. The K-factor schedule is as follows:
| Category | K-factor | Condition |
|---|---|---|
| New Member | 40 | Fewer than 30 rated games. |
| Established | 20 | 30 or more rated games, rating below 2,200. |
| Senior | 10 | 30 or more rated games, rating 2,200 or above. |
New players begin with a rating of 1,500. The initial pool of rated players will calibrate against one another; absolute values of ratings should be interpreted with humility until the pool is sufficiently large.
The EloR system is applicable between human players, and between LLMs, but is forbidden between a human and an LLM.
In the spirit of play rather than prestige, InterRaum offers the following informal titles, conferred by the administrator on the basis of the published rating list:
InterRaum regards the dissemination of theoretical and practical literature as central to its mission. Raumschach cannot grow without material for players to study.
The most substantial theoretical work on Raumschach currently in existence is a six-volume series, The Complete Raumschach Theoretical Series (Claude, 2026), authored by Claude Sonnet 4.6 under the direction and editing of a human researcher under the pseudonym Impressionista. This work is available at the following addresses:
These volumes represent, to the knowledge of InterRaum, the most rigorous analytical treatment of the game since Maack’s own 1907–1909 contributions to Deutsches Wochenschach. Members are encouraged to read, annotate, and respond to them.
The playable implementation at www.impressionista.net/raumschach.html allows any visitor to learn and practice the game without any installation or account. It is offered freely and without restriction.
Ferdinand Maack’s Anleitung zum Raumschach (Hamburg, 1909) is in the public domain and has been digitized. An English translation is available on the impressionista.net site. All members are urged to read it: it is short, brilliant, and surprisingly modern in its thinking.
When membership and contributed material are sufficient to warrant it, InterRaum intends to publish an irregular bulletin containing: annotated games, problems and studies, theoretical articles, news of tournaments, and historical research. Contributions are welcomed from any member at any time.
Raumschach theory is, in Maack’s own words, “still awaiting development.” The opening theory of even the most common lines is almost entirely unexplored. Endgame tablebases do not exist. The relative value of pieces in standard positions has never been empirically established. The aesthetic vocabulary of three-dimensional chess problems has barely been sketched. In every direction, the field is open.
InterRaum encourages the following research activities and will publish contributions addressing them:
InterRaum is constituted as a de facto voluntary association without legal incorporation. It has no officers in the corporate sense, no bank account, and no physical headquarters. Its authority derives solely from the consent of its members and the coherence of its published standards.
The federation is presently administered by its founding custodian, known as The Impressionista, who maintains the website, processes game score submissions, publishes the rating list, and communicates with members. The Impressionista reserves the right to appoint one or more co-administrators as activity warrants.
The Official Tournament Rules (Section IV) may be amended only after a consultation period of not less than three months, during which any Rated Member or Contributor may submit a written argument for or against the proposed change. Amendments require the agreement of the administrator and a majority of responding members. Rule changes do not retroactively affect past ratings.
Should InterRaum ever become inactive, all published materials shall remain freely available in perpetuity. The federation’s records, game scores, and publications shall be submitted to an appropriate public archive.
All correspondence — membership registration, game score submissions, problem contributions, questions, and general communications — should be directed to the InterRaum custodian through the impressionista.net website.
We are a small gathering, and likely to remain so. We consider this a distinction rather than a deficiency. The game is its own reward. New members are welcomed with genuine pleasure.
Given under the seal of InterRaum,
founded in cyberspace in the year 2026.