Est. 2026 · Three-Dimensional Chess
The Art of Chess in Three Dimensions
The governing body for the study, play, and advancement of Raumschach — the original three-dimensional chess invented by Ferdinand Maack in 1907. Non-commercial. Rigorous. Open to all.
Origin & History
Raumschach — from the German Raum (space) and Schach (chess) — is the three-dimensional chess variant invented by Dr. Ferdinand Maack of Hamburg in 1907. Played on a stack of five 5×5 boards, it extends the classical geometry of chess into a third dimension, introducing the Unicorn, a piece that moves along all four triagonal directions.
Unlike later three-dimensional variants, Raumschach was designed with austere theoretical rigor. Its rules are an organic extension of orthodox chess, and its opening theory, endgame structure, and strategic principles remain largely uncharted — an intellectual frontier of extraordinary depth.
The IRF is dedicated to building the canonical body of Raumschach theory, hosting competitive play, and preserving the historical record of the game from the original writings of Maack through to the present day.
The 5×5×5 Board
Five levels · 125 squares · Infinite geometry
Online Play
Play a live remote game nearly anywhere via Signal, or pass-and-play in correspondence style, or if opportunity presents, play in person. Full tournament-legal rule set with optional chess clock.
Test your understanding against an AI opponent across six difficulty levels. Ideal for studying patterns, practising tactics, and exploring opening ideas.
An integrated Elo rating calculator lets players track competitive results using standard FIDE K-factor methodology adapted for Raumschach.
The IRF game client requires no installation and no account. Open it in any modern browser and begin immediately. All rules are enforced automatically, including the triagonal movement of the Unicorn and three-dimensional check detection.
Competitive Play
Theoretical Literature
The six-volume theoretical series published here is the most comprehensive treatment of Raumschach. The work covers the complete rule set, piece taxonomy, geometric theory, opening principles, and endgame structure of the game.
Primary Reference
All theoretical analysis is verified against Anthony Dickins, A Guide to Fairy Chess (1969/71), the authoritative historical source for variant piece taxonomy and rule disambiguation.
Visit Dickins →Errata
Known corrections to the published series are maintained in a living errata document, updated as errors are identified and traced to authoritative sources.
View Errata →The Organization
The International Raumschach Federation is a non-commercial organization. Its sole purpose is the promotion and study of Raumschach at a rigorous level consistent with the historical and theoretical dignity of this game.
I
The IRF accepts no membership fees, and sells no products. The game is a public intellectual heritage and shall remain freely accessible to all.
II
All published theory, rulings, and analysis issued under the IRF name are held to an evidentiary standard. Ambiguities are resolved by reference to primary historical sources.
III
Membership, tournament participation, and access to theory are open to anyone, worldwide, regardless of level. No registration beyond a name is required to play in an IRF event.
IV
The IRF maintains and publishes the definitive rule set for competitive Raumschach, grounded in the original specifications of Maack and corrected against the historical record.
V
The IRF documents the history of Raumschach: its invention in 1907, its published history, its appearances in variant literature, and its competitive legacy.
VI
To become a member, to register for a tournament, or to submit a theoretical inquiry or correspond on federation matters, contact the IRF. All correspondence is welcome.