2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/139293In the Byzantine Empire of 11-15 CE chess was played on the circular board. Two versions were known - REGULAR and SYMMETRIC. The difference between them is easy: the white queen is placed either on light (regular) or on dark square (symmetric). However, the computer analysis reveals the results of this 'small perturbation'.History and OverviewGeneral Mathematics:91A05, 91A80text