Related Clues:

• Large fortified building
• Keep a rook on board
• Keep this on board for a rook
• If there's a rook on board, keep it
• There's a rook on board
• Keep fifty in class
• Keep a rock on board
• Keep this piece on board
• Throw away - or keep - the French
• Let's keep confused under the accountant
• The bits that move about on board
• Keep a rook that moves aside on board
• Keep a rook to the fore on board
• Keep a piece - of 1 across, perhaps, on board
• Keep what might be a 17 down