A hexagon cut into three sectors, one per player, meeting at the centre. Each sector is a half-board of two quadrilaterals, so three players each get a board of their own that joins the others at the middle. Pieces stand in the cells or where the lines cross.
The topology names every cell by its sector, file and rank as its owner reads them, and knows where the lines fork at the centre. The chess plugin plays Yalta on it without knowing it is not a chessboard.
Three-player chess on 96 quadrilateral cells: three boards of 32, one per player, meeting at the centre where the lines fork.
engine:
topology:
type: hexagonal-trisection
players: [red, green, blue]Yalta Chess: three sectors, three armies
Three players, three half-boards, one centre.