Capablanca chess

Capablanca chess expands the board to ten files, or vertical columns, and eight ranks, or horizontal rows. Each side keeps the familiar army and gains two new pieces. The extra width creates more space, while the basic rules of movement, capture, check, meaning an attack on the king, and checkmate, an attack with no legal reply, remain recognizable.

The two compound pieces

• The archbishop can move as either a bishop or a knight. It chooses one of those movements on a turn rather than making both in sequence.
• The chancellor can move as either a rook or a knight. It likewise chooses one of its two movement types for each move.

They are called compound pieces because each combines the full powers of two ordinary pieces. The knight component lets them jump, while the bishop or rook component gives long-range movement whenever the path is clear.

When a pawn reaches the last rank, it may promote, meaning that it is replaced by a stronger piece. The available choices include the archbishop and chancellor. Castling, the special move involving king and rook, is also adapted to the wider board: in a common setup the king travels three squares instead of two.

Capablanca proposed the variant in the 1920s, and related implementations use more than one starting arrangement. Players should therefore check the displayed setup before beginning. The 10-by-8 board and the archbishop-chancellor pair remain the defining features.

It is not the same as Grand Chess. That game uses a 10-by-10 board and equivalent compound pieces called the cardinal and marshal, but it changes the setup, removes castling, and has a different promotion rule.