Slav Defense: Czech Variation, Krause Attack

Slav Defense: Czech Variation (a.k.a. Chebanenko Slav)

Definition

The Czech Variation of the Slav Defense is defined by Black’s early …a6 in the main starting position of the Slav:

1. 1. d4 d5
2. 2. c4 c6
3. 3. Nf3 Nf6
4. 4. Nc3 a6

The move 4…a6 is the signature of the variation. It prepares …b5 to protect the c4-pawn after …dxc4, restrains White’s minority attack with b2-b4, and waits to commit the light-squared bishop.

Strategic Themes

• Flexibility. Black keeps options open: the queen’s bishop may go to f5, g4, d7, or even b7 after …b5, while the central pawn break …e5 can be prepared in many move orders.
• Queenside space. After …a6 and …b5 Black often gains territory on the queenside, sometimes following up with …c5.
• Delayed decision on …dxc4. Black can capture on c4 immediately, defer the capture, or omit it entirely, depending on White’s set-up.
• White’s choices. Five moves occur in hundreds of grand-master games:
  • 5.a4 – stops …b5 and tests Black’s flexibility.
  • 5.c5 – clamps down on …b5 and …e5 (leads to the Krause Attack).
  • 5.e3 – a quiet, solid approach.
  • 5.g3 – blends Catalan development with the Slav structure.
  • 5.Qc2 (or 5.Qb3) – puts pressure on b7 and d5 immediately.

Historical Notes

Although “Czech” appears in the name, the line was developed in the 1960s and 70s by the Moldovan trainer and theoretician GM Vitaly Chebanenko. When his pupils – notably Bologan and Komarov – began scoring excellent results, the variation spread rapidly. It is now a mainstay in elite chess; Kramnik, Ivanchuk, Topalov, and Carlsen have all trusted it in critical games.

Illustrative Mini-Game

Topalov – Kramnik, Linares 2004 (moves 1–15):

The game continued dynamically and was eventually drawn after 33 moves. It shows the fluid piece play and queenside tension typical of the variation.

Interesting Facts

• The move …a6 appears “slow,” but engines evaluate the position as fully playable for Black – a testament to modern opening philosophy.
• Because Chebanenko was from Moldova, Russian sources often call it the “Chebanenko Slav,” while English texts favor “Czech Variation.”
• In 2006 the variation made headlines when Topalov used it in his World Championship match versus Kramnik, scoring +1 −1 =4 with the system.

Krause Attack (within the Czech/​Chebanenko Slav)

Definition & Move Order

The Krause Attack is White’s most forceful reply to 4…a6, characterized by an immediate advance of the c-pawn, followed by development that supports the space-gaining bind:

1. 1. d4 d5
2. 2. c4 c6
3. 3. Nf3 Nf6
4. 4. Nc3 a6
5. 5. c5!

After 5…Bf5 (the most common), typical continuations are 6.Bf4, 6.Nh4, or 6.g3. The name honors German master Hermann Krause, who championed the early c4-c5 idea in the 1920s.

Strategic Ideas

• Space & restriction. By fixing the pawn chain on dark squares (d4–c5–b4), White gains queenside space and cramps Black’s …b5 break.
• Knight outposts. The square b6 can become a permanent weakness; White often maneuvers Nb1–d2–b3–a5 or Ne5–c4.
• Minor-piece activity. Both bishops usually emerge to f4 and d3 (or g2) where they point toward the kingside, keeping options for an eventual e2-e4 break.
• Black’s counterplay.
  • …Nbd7 followed by …e5 attacks White’s center.
  • …g6 aiming for a Grunfeld-style structure.
  • Delay …Bf5 and hit the center with …e5 immediately.

Sample Line

A common tabiya arises after:

The position is rich: White owns more space, Black has a solid structure and the long-term break …e5 in reserve.

Why Choose the Krause?

• Independent play. The early pawn thrust steers the game away from heavily analyzed 5.a4 lines.
• Practical pressure. Club players often mis-handle the cramped Black position, giving White an easy initiative.
• Theory-light. Compared with 5.a4 or 5.e3, fewer razor-sharp forcing variations exist.

Historical & Modern Usage

Krause’s idea lay dormant for decades, but the computer era has revived interest. GM Alexey Shirov and GM Baadur Jobava have scored notable victories with the system, and it is a favorite “surprise weapon” in rapid and blitz chess.

Trivia

• In some databases the Krause Attack is mislabeled “Shirov Variation,” reflecting Shirov’s success with the line in the 1990s.
• Because the c-pawn is already on c5, White’s minority-attack idea b2-b4-b5 from the Exchange Slav has an echo here, but arrives a tempo faster.
• Engines often fluctuate wildly in evaluation after 5.c5, showing how strategically double-edged the fixed structure can be.