A Game That Never Was: Verney's Duodecimal Chess

Georgi Markov's article examines a 12x12 chess variant that arose from a series of misreadings by G. H. Verney, author of Chess Eccentricities (1885). Verney's description of a "game by Alfonso X" and his account of Courier Chess appear to derive from misinterpreting diagrams and rules in A. van der Linde's Quellenstudien zur Geschichte des Schachspiels and H. C. Albers' 19th-century "improved" Courier Chess. Markov argues that Verney, by combining an out-of-context diagram with Albers' rules and piece moves, unintentionally produced a hybrid game that never existed historically, which he proposes calling Verney's Duodecimal Chess.

The study's central finding is that the game, despite its accidental origins, is surprisingly playable. Its pieces include unicorns (moving as bishop plus knight), a "king's councillor" (king plus knight), and a "queen's fool" (a non-royal king), placed on a board with the pieces in the setup RNUBFQKCBUNR. Markov traces specific errors, such as the reversed viewpoint of the diagrams and the substitution of Albers' pieces for medieval ones, to show how the game's configuration emerged. Because Verney's text is incomplete, the article supplies a full rule set, including a modified Turkish castling method and, as an alternative, Albers' whimsical rules on pawn promotion and castling.

The scope is limited to historical analysis of 19th-century chess literature, drawing on primary sources, modern scholarship, and comparisons of diagrams and textual descriptions rather than on empirical play testing. The conclusion characterizes the episode as a notable case of serendipity in chess variant history.