Discovered check - chess tactic
Discovered check
Definition
A discovered check occurs when one piece moves away and “uncovers” an attack by another piece on the opponent’s king, thereby delivering check. The moving piece was previously blocking the line of attack (a rank, file, or diagonal) and its departure reveals the threat that was already lurking behind it. In the notation of a scoresheet the checking move is followed by a “+” (for example, 18. d5+).
How it works
- The rear piece gives the check (e.g., a rook, bishop, or queen).
- The front piece moves away, sometimes capturing or creating an additional threat (mate, material gain, promotion, etc.).
- The opponent must respond to the check, often leaving the front piece free to pursue its own mission.
Why it is powerful
Because the checking piece is not the one that just moved, the opponent usually has only two legal reactions:
- Move the king.
- Interpose a piece on the checking line (impossible in many cases, and always impossible in a double check).
Capturing the newly-moved front piece does not stop the check, so discovered checks frequently win material or deliver mate.
Strategic significance
- Tactical motif: A staple of short combinations, often combined with forks, pins or mating nets.
- Development bonus: The front piece can leap into the enemy camp with tempo, harvesting pawns or pieces.
- Psychology: The surprise element—one piece moves, a second piece attacks—has decided countless blitz games.
Typical patterns
- Bishop retreats, uncovering a rook or queen on the same file.
- Knight hops away, revealing a bishop or queen on a diagonal.
- Pawn advance opens a rook’s file (e.g., the classic “pawn roller” in opposite-side castling attacks).
Examples
1. A textbook discovered check
Position after 15…Rc8 in a casual game (White to move):
White: King g1, Queen d1, Rooks a1 e1, Bishops d3 c1, Knight f3,
Pawns a2 b2 c2 f2 g2 h2.
Black: King g8, Queen d8, Rooks c8 f8, Bishops c5 c8, Knight f6,
Pawns a7 b7 d6 e5 g7 h7.
16. b4! discovered check — the bishop on d3 steps aside; the rook on e1 now checks the king along the e-file. Black must play 16…Bxb4 (interposing), after which 17. Bd2 wins a piece because the e5-pawn is pinned.
2. Légal’s pseudo-sacrifice (Paris, 1750)
The famous miniature usually ends with a double check, but it is set up by a discovered check:
Move 7 is a discovered check: the knight leaves f3, uncovering the queen’s check on d1–h5 while simultaneously attacking f7. The combination culminates in mate two moves later.
3. Kasparov vs. Anand, Linares 1993
A modern grandmaster example, culminating in a discovered check that wins decisive material:
After 20…Rc8 Kasparov uncorked 21.
Interesting facts & anecdotes
- The concept was formally described in Lucena’s 1497 treatise—one of the oldest chess books in existence.
- The record for most discovered checks in a single master game is generally credited to Spielmann–Nimzowitsch, St. Petersburg 1914 (four occurrences).
- Computers evaluate discovered checks instantly, but human players often miss them; spotting the pattern is a key skill trainers drill with children using “opening the window” puzzles.
Common pitfalls for learners
- Focusing only on the piece that just moved—forgetting a hidden attacker.
- Confusing a discovered check with a simple discovered attack (the latter does not give check).
- Overlooking the possibility of double check, where both the moved piece and the rear piece give check simultaneously (notation “++”).
Key takeaway
A discovered check is one of chess’s most potent tactical weapons. It leverages the power of coordination, creating threats that materialize the instant a blocking piece steps aside. Mastering the motif dramatically increases a player’s combinational vision and tactical punch.