Related Clues:

• Pen pal?
• Man who would be queen?
• Promotable piece
• Unwitting accomplice
• One may be placed before a king
• Kind of shop
• Hoosegow occupant
• Future queen?
• Chess piece
• Front-rank piece
• One ahead of a bishop
• Locked up
• Kasparov's soldier
• Target of promotion
• It's usually moved first