Slav Defense: Modern Alapin, Czech & Krause Attack
Slav Defense
Definition
The Slav Defense arises after the moves 1. d4 d5 2. c4 c6. Black immediately supports the d5-pawn with the c-pawn rather than the more common …e6 (Queen’s Gambit Declined). This small change alters the pawn structure, frees the light-squared bishop, and lays the foundation for one of the most solid and theory-rich queen-pawn openings.
Typical Move-Order & Branches
- Main line: 3. Nf3 Nf6 4. Nc3 (or 4. e3) — after which the opening branches into the Modern, Alapin, Czech, Chebanenko, and other variations.
- Exchange Variation: 3. cxd5 cxd5, leading to symmetrical but subtle play.
- Geller–Tolush, Semi-Slav & Meran set-ups when Black adds …e6, entering a hybrid structure.
Strategic Themes
- Solid pawn shield. The c6–d5 pawn chain makes d5 extremely hard to break, giving Black a rock-solid centre.
- Light-squared bishop freedom. Unlike in the QGD, Black’s c8-bishop can often leave the pawn chain before …e6 is played.
- Minority attack potential. In many Exchange Slav structures, White’s b-pawn advances (b4-b5) to create queenside weaknesses.
- Dynamic counterplay. Lines with …dxc4 yield an extra pawn that Black tries to hold with …b5, creating sharp tactical battles.
Historical Significance
The Slav grew popular in the early 20th century; masters such as Akiba Rubinstein and later Vassily Smyslov used it as a reliable drawing weapon. In modern times, Vladimir Kramnik, Viswanathan Anand and Magnus Carlsen all employ it at the highest level, cementing its reputation as an elite, theory-dense defence.
Illustrative Game
Kramnik – Topalov, WCh (Game 2), 2006
1.d4 d5 2.c4 c6 3.Nf3 Nf6 4.Nc3 dxc4 5.a4 Bf5 6.e3 e6 7.Bxc4 Bb4 8.O-O Nbd7 ½-½
A model demonstration of the rock-solid nature of the Slav; neither side could create winning chances.
Interesting Facts
- The ECO codes for the Slav run from D10 to D19, more than any other queen-pawn defence.
- The name “Slav” stems from its popularity among Eastern-European masters in the 1920s.
Modern Variation of the Slav
Definition
The term “Modern Slav” usually refers to the set-up 1.d4 d5 2.c4 c6 3.Nf3 Nf6 4.e3 a6 (or 4…Bf5/…dxc4 followed by the key …a6). The move …a6 gives Black flexible queenside options—…b5 to hold the c4-pawn, or …dxc4 followed by …b5—while waiting to decide on …e6 or …g6 setups.
Why the Move …a6?
- Prepares …b5, anchoring an extra c4-pawn.
- Restricts White’s knight jump Nb5 (annoying in some lines).
- Offers a waiting move, keeping the central tension and choice of …e6 or …g6 open.
Strategic Considerations
- Queenside expansion. After …dxc4 …b5 Black seizes space on the flank.
- Delayed development. Black postpones committing the c8-bishop, leaving White uncertain which plan to pursue.
- Balanced risk. …a6 slightly weakens b6 and slows development, so accuracy is required.
Sample Line
After 6…b5 Black keeps the extra pawn and plans …e6, …Nbd7, …Bb7 with solid chances.
Notable Use
Grandmaster Alexey Shirov employed this line repeatedly in the late 1990s, sharpening it with early …g6 ideas to create imbalances.
Alapin Variation (in the Slav)
Definition
The Alapin Variation of the Slav appears after 1.d4 d5 2.c4 c6 3.Nf3 Nf6 4.e3. Named after Russian theoretician Semyon Alapin, White quietly reinforces the d4-pawn and opens a path for the dark-squared bishop instead of the sharper 4.Nc3 lines.
Key Ideas for White
- Smooth development. White aims for Bd3, Qc2, and often b3/Bb2, casting long or short according to Black’s set-up.
- Central stability. By protecting the c4-pawn with the bishop (after b3/Bb2) or pawn (a theoretical 5.cxd5), White blunts …dxc4 ideas.
- Flexibility. White can later choose between minority-attack structures (cxd5 exd5) or central pawn breaks (e4).
Common Black Replies
- 4…Bf5 (Czech variation overlap)
- 4…e6 (heading toward a Semi-Slav flavour)
- 4…g6 (accelerated fianchetto)
Example Continuation
1.d4 d5 2.c4 c6 3.Nf3 Nf6 4.e3 Bf5 5.Nc3 e6 6.Nh4 Bg4 7.Qb3!
White pressures b7 and forces Black to solve piece placement issues, illustrating the positional venom hidden behind the modest 4.e3.
Anecdote
World Champion Anatoly Karpov frequently chose 4.e3 in the 1970s, mirroring his patient, prophylactic style—often out-maneuvering tactical experts who underestimated the line.
Czech Variation of the Slav
Definition
The Czech Variation is reached after 1.d4 d5 2.c4 c6 3.Nf3 Nf6 4.Nc3 dxc4 5.a4 Bf5. By developing the bishop outside the pawn chain before committing to …e6, Black both defends the c4-pawn and accelerates development.
Strategic Essence
- Hanging pawn dilemma. Black clings to the extra c-pawn, inviting White to over-extend trying to recover it.
- Active minor pieces. Both of Black’s bishops are outside the chain (…e6 later), giving tactical bite.
- Queenside structure. …c6–c5 break or …b5 support are thematic; White counters with e4 or castling long with central thrusts.
Theoretical Hotspot: 6.Nh4!
After 6.Nh4 Bf5, White often plays 7.f3 or 7.e4, challenging the bishop. Black must know precise replies (…e6, …Nd5) to avoid falling into cramped positions.
Classic Encounter
Kasparov – Bareev, Linares 1993
1.d4 d5 2.c4 c6 3.Nf3 Nf6 4.Nc3 dxc4 5.a4 Bf5 6.Nh4 Bg6 7.f3 e5!? Kasparov uncorked a pawn sacrifice to rip open the centre, showcasing the dynamic richness of the Czech Slav.
Trivia
- The variation is “Czech” because early analysis came from Prague masters—chiefly Karel Hromádka—in the 1920s.
- The same name appears in other openings (e.g., Czech Benoni, Czech Pirc); context is key.
Krause Attack
Definition
The Krause Attack targets the Czech Slav and begins with 6.Ne5!? after 1.d4 d5 2.c4 c6 3.Nf3 Nf6 4.Nc3 dxc4 5.a4 Bf5. German master Paul Krause introduced the idea in 1911, immediately challenging Black’s aggressive bishop with a tactical knight leap.
Main Line
After 6.Ne5 e6 7.f3 Bb4 8.e4 White builds a powerful centre, threatens g4 chasing the bishop, and readies Bxc4 recapture. Black can counter with 8…Bxe4 or 8…Bg6, each leading to razor-sharp play.
Strategic & Tactical Motifs
- Outpost on e5. The knight obstructs …e6-e5 freeing plans, buying time for White to seize the centre.
- Super-charged centre. White’s f- and e-pawns advance, mirroring King’s Gambit-style violence in a queen-pawn opening.
- Piece activity vs. pawn structure. Black keeps the extra pawn but must navigate concrete tactical landmines.
Model Game
Grischuk – Aronian, Tal Memorial 2006
1.d4 d5 2.c4 c6 3.Nf3 Nf6 4.Nc3 dxc4 5.a4 Bf5 6.Ne5 e6 7.f3 Bb4 8.e4 Bxe4 9.fxe4 Nxe4 10.Qg4!! Both kings end up wandering while spectators held their breath—an excellent illustration of the attack’s ferocity.
Interesting Nugget
Because the move 6.Ne5 was considered “too dangerous for Black” in pre-computer days, some grandmasters avoided 5…Bf5 altogether; the modern engine era has rehabilitated Black’s chances, sparking a theoretical arms race that continues today.