Chess Special Rules – Castling, En Passant & Promotion
🏰 Castling – Protecting Your King and Connecting Rooks
Castling is the only move where two pieces — the king and a rook — move at the same time.
It helps bring your king to safety and connects your rooks.
King-side castling: The king moves two squares toward the rook on h1/h8, and that rook jumps over to f1/f8.
Queen-side castling: The king moves two squares toward the rook on a1/a8, and that rook jumps over to d1/d8.
Conditions for castling:
Neither the king nor the chosen rook has moved before.
No pieces are between the king and rook.
The king is not in check, and the king cannot move through or into check.
Before castling – White King moves 2 squares (Gold), Rook jumps over (Orange).
After castling – White has castled kingside. King safe, Rook active.
⚔️ En Passant – The “In Passing” Capture
En passant is a special pawn capture that can only occur immediately after an opponent moves a pawn two squares forward from its starting rank.
If your pawn could have captured it had it moved just one square, you may capture it as if it had done so.
It’s a rule designed to keep pawn structure fair and prevent pawns from bypassing attacks unfairly.
Before en passant – Black played d7–d5. White captures on d6 as if the pawn moved one square.
After en passant – White captures the black pawn “in passing” with exd6 e.p.
👑 Pawn Promotion – Reward for Reaching the Last Rank
When a pawn reaches the farthest rank (the 8th for White, the 1st for Black), it must be promoted to another piece —
a queen, rook, bishop, or knight (you cannot promote to a king).
In almost all cases, promoting to a queen is best — this is called a queening.
Sometimes, though, promoting to a knight can deliver a surprising check or checkmate (known as underpromotion).
Before promotion – White pawn on e7 ready to advance to e8.
After promotion – White pawn becomes a queen on e8 (=Q), checking the King.
💡 Quick Summary
Castling: Move the king and rook together to protect your king.
En Passant: Capture a pawn that moved two squares as if it moved one.
Promotion: Turn your pawn into a stronger piece when it reaches the far rank.
✅ Practice Tip
These special rules often appear in tactics puzzles and endgames.
Practice them regularly so you can use them automatically during games!