…Bb4+ check

…Bb4+ (The Bishop Check on b4)

Definition

The symbol “…Bb4+” denotes Black’s bishop moving to the square b4, giving check to the white king. The ellipsis (…) shows the move is made by Black, B is the bishop, b4 the destination square, and the plus sign (+) indicates check. Because the bishop starts on f8 in the initial position, the move involves a long diagonal sweep (f8–e7–d6–c5–b4).

Strategic Idea

…Bb4+ is more than a simple check:

• Forcing Moves: White must respond immediately, often limiting their choices and helping Black dictate early play.
• Pin and Pressure: When White’s knight sits on c3 (or a white bishop on d2), the check can pin that piece to the king or force awkward blocking moves such as 4. Bd2 or 4. Nc3.
• Structural Considerations: After …Bb4+ and eventual …Bxc3, Black sometimes doubles White’s c-pawns, creating long-term weaknesses.
• Development and Initiative: Delivering a check on move three or four can accelerate Black’s development while delaying White’s.

Typical Openings Featuring …Bb4+

• French Defence, Winawer Variation 1. e4 e6 2. d4 d5 3. Nc3 Bb4+
• Caro-Kann Defence, Tartakower (Fantasy) Line 1. e4 c6 2. d4 d5 3. f3 dxe4 4. fxe4 e5 5. Nf3 Bb4+
• Bogo-Indian Defence 1. d4 Nf6 2. c4 e6 3. Nf3 Bb4+
• Petrov Defence, Steinitz Variation 1. e4 e5 2. Nf3 Nf6 3. d4 Nxe4 4. Bd3 d5 5. Nxe5 Bb4+

Illustrative Game Snapshot

Below is the classic starting sequence of the Winawer, perhaps the most famous home of …Bb4+.

Key choices for White after the check:

1. 4. Bd2 (force bishop exchange, solid but passive)
2. 4. Nc3 (illegal because knight already on c3!)
3. 4. Qd2 (rare sideline, protecting the knight and aiming to castle long)
4. 4. exd5 (entering the branch known as the “Winawer Exchange”)

Historical Notes & Anecdotes

• The Winawer Variation is named after Polish master Stanisław Winawer, who popularized the idea of pinning on b4 in the 19th century.
• In the 1990 Candidates’ match between Karpov and Hübner, Karpov’s 4. e5!? against the Bogo-Indian’s …Bb4+ surprised experts and helped him win the game.
• Computer engines now show that in some French lines White may allow doubled c-pawns after …Bxc3+, playing for space and the bishop pair—illustrating how evaluation of …Bb4+ has evolved.

Practical Tips

• Before playing …Bb4+, ensure the check truly disrupts White’s plans; if White can easily block with Bd2 and gain time, the move loses punch.
• If you intend to exchange on c3, have a follow-up plan for the half-open b-file you give White.
• Against 1. d4 systems, remember the bishop may retreat to e7 or back to f8 later; avoid letting it get trapped by an a3 advance.

Quick Reference Table

• First recorded appearance: Paris, 1867 (Winawer)
• Most common modern context: French Defence Winawer
• Main tactical themes: pin, double attack on king and c3-knight, doubled pawns
• Typical follow-ups for Black: …c5, …Ne7, …Nc6, or rapid queenside castling