Invented in 1747 by John Manners, third Duke of Rutland. A 14×10 board carries the usual army (King, Queen, 2 Rooks, 2 Knights, 2 Bishops) plus 2 Crowned Rooks (rook + one diagonal step, like a ferz), 1 Concubine (rook + knight combined), and 1 extra Knight, 2 extra Bishops. Pawns may advance 1, 2, or 3 squares on their first move.
Simplifications: en passant and castling are omitted (the historical castling rule is itself unrecorded). A pawn reaching the last rank auto-promotes to a queen (originally a choice among queen, concubine, rook, crowned rook, bishop, or knight). Check and checkmate aren't enforced — capturing the king directly ends the game. Amusingly, 18th-century English rules of the time held that stalemating your opponent made you lose — this implementation's "no legal moves means you lose" happens to land on the same result either way.