Slav Defense Modern Triangle Anti-Noteboom Beliavsky Line

Slav Defense

Definition

The Slav Defense is a highly respected reply to the Queen’s Gambit that begins 1.d4 d5 2.c4 c6. Black supports the central pawn on d5 with the c-pawn, refusing to concede the center and keeping the light-squared bishop on c8 free. ECO codes range from D10–D19.

Typical Move-Order

1.d4 d5
2.c4 c6
3.Nf3 Nf6
4.Nc3 dxc4 (main line), or 4…e6 (Semi-Slav), or 4…a6 (Chebanenko)

Strategic Ideas

Solid pawn structure: the c6–d5 chain is very hard to undermine.
Flexible development: the queen’s bishop can be fianchettoed to f5 or g4 before …e6 is played.
Minor-piece play: both sides maneuver around the symmetrical pawn skeleton looking to seize small imbalances.

Historical Significance

The Slav was popularized in the early 1920s by Czech and Russian masters and became a backbone of the Soviet repertoire. World Champions such as Botvinnik, Smyslov, Kramnik, and Carlsen have all relied on it in critical games.

Illustrative Game

[[Pgn|d4|d5|c4|c6|Nf3|Nf6|Nc3|dxc4|a4|Bf5|e3|e6|Bxc4|Bb4|O-O|Nbd7|Qe2|Bg6|e4|O-O|Bg5|Qa5|e5|Nd5|Ne4|h6|Bh4|N7b6|Bd3|Nf4|Qe3|Nxd3|Qxd3|Qd5|Nfd2|c5|Nc4|cxd4|Nxb6|axb6|Nxb6|Ra6|Nxd5 exd5|Qxd4 Qxd4|Kh1|Rfa8|Rad1|Ra2|Rxd4|R8a5|Rb4|R5a4|Rxa4 Rxa4|Rxa4 Bxh4|| |arrows|d4d5,c4c6|squares|d5,c6,c4]]

Carlsen–Anand, World Championship 2013 (Game 6). Carlsen’s subtle endgame pressure in the Slav endgame eventually produced a famous win.

Interesting Facts

The Slav is one of the few 1.d4 defenses where Black can keep the c8-bishop outside the pawn chain.
An early 4…a6 Chebanenko Slav was “rediscovered” by Moldovan GM Viktor Chebanenko and later adopted by Kramnik against Kasparov in their 2000 match.

Modern Triangle System

Definition

The Modern Triangle (also called the “Triangle System” or “Triangle Slav”) is a setup for Black characterized by the pawn triangle c6–d5–e6. A typical move-order is 1.d4 d5 2.c4 e6 3.Nc3 c6. By playing …e6 before …c6, Black keeps multiple transpositional options: Slav, Semi-Slav, or Queen’s Gambit Declined.

Key Ideas

Flexibility: depending on White’s 4th move, Black can enter a Noteboom, the Marshall Gambit, the Anti-Meran, or a Cambridge Springs setup.
The triangle restricts White’s center while allowing rapid development of kingside pieces.
Pawns on dark squares leave the light-squared bishop free but hem in the dark-squared bishop—Black often aims for …Bd6 or …Be7 followed by …dxc4.

Critical Lines

Marshall Gambit: 4.e4 dxe4 5.Nxe4 Bb4+. Sharp, forcing play.
Noteboom Variation: 4.Nf3 dxc4 5.e4 b5 – an ambitious pawn grab.
Anti-Noteboom: 4.e3, 4.g3, or 4.a4 (examined below).

Historical Snapshot

Although the triangular structure occurred as early as the 19th century, its systematic treatment is modern—hence the name. It became fashionable in the 1990s after being refined by Ivanchuk, Anand, and the Dutch GM Jeroen Piket.

Example Miniature

[[Pgn|d4|d5|c4|e6|Nc3|c6|e4|dxe4|Nxe4|Bb4+|Bd2|Qxd4|Bxb4|Qxe4+|Be2|Qg6|Nd6+|Kd7|Nf3|Qxg2|Rg1|Qh3|Ne5+|Kc7|Ndxf7|Qxh2|Ba5+|b6|Rxg7|Qh1+|Bf1|Qe4+|Qe2|Qxe2+|Kxe2|bxa5|Nxh8+|Kb6|Rxg8|Ba6|Ke3|Nd7|Nxd7+|Kc7|Rxa8 h5|| ]]

White’s 4.e4 Marshall Gambit leads to wild positions—great for surprise value.

Anecdote

During the 2004 FIDE Knock-out Championship, Veselin Topalov employed the Modern Triangle four times with Black, scoring +2 =2 -0 and crediting its “elasticity” as the reason he avoided revealing his main openings.

Anti-Noteboom

Definition

The Anti-Noteboom refers to White systems designed to sidestep or neutralize the sharp Noteboom Variation (1.d4 d5 2.c4 e6 3.Nc3 c6 4.Nf3 dxc4 5.e4 b5). Because the Noteboom can lead to unbalanced pawn structures that many Queen’s Gambit players dislike, Anti-Noteboom lines—most notably 4.e3, 4.g3, or 4.a4—aim to prevent …dxc4 or make it unattractive.

Most Popular Anti-Noteboom Weapons

4.e3 – Classical development, supported by the Belyavsky Line (5.f4!).
4.a4 – The early rook-pawn prevents …b5, undercutting Black’s main idea.
4.g3 – Fianchetto variation, keeping long-term pressure on d5 and c6.

Strategic Themes

Maintain the central pawn duo on c4 and d4, avoiding structural weaknesses.
Exploit the slight passivity of Black’s dark-squared bishop constrained by …e6.
Steer the game into QGD-style positions rather than Slav pawn-grabs.

Model Game

[[Pgn|d4|d5|c4|e6|Nc3|c6|e3|Nf6|Nf3|Nbd7|Qc2|Bd6|g4|Nxg4|Rg1|Nxh2|Nxh2|Bxh2|Rxg7|Qh4|e4|dxe4|Nxe4|Kf8|Bg5|Qh5|Be2|Bb8|Qd2|Qh1+|Bf1|Qxe4+|Be2|Qh1+|Bf1|Qxe4+|Be2|Qh1+|Bf1|Qxe4+|| ]]

Here White’s 4.e3 and 6.g4!? (Anti-Noteboom by force) led to a swashbuckling attack in Jobava-style.

Trivia

The term “Noteboom” comes from the Dutch player Daniël Noteboom, who introduced the pawn-grab idea in the 1930s. Ironically, modern Dutch grandmasters such as Erwin l’Ami now specialize in the Anti-Noteboom with White!

Belyavsky Line

Definition

The Belyavsky Line is a particular Anti-Noteboom set-up that arises after 1.d4 d5 2.c4 e6 3.Nc3 c6 4.e3. Named after the Slovenian GM Alexander Beliavsky (the spelling “Belyavsky” is also common), it prepares a quick f2-f4 thrust and keeps options to recapture on c4 with the bishop if Black takes early.

Main Continuation

4…Nf6 5.Nf3 or 5.f4
If 4…dxc4 5.Bxc4 b5 6.Bd3 keeps a solid center and targets the weakened queenside.

Typical Plans for White

Support e4 with f2-f4 and eventually e3-e4, claiming space.
Develop the dark-squared bishop actively (Bd3 or Bb5+).
Castle kingside and conduct a minority attack with b2-b4 when appropriate.

Why It Works

Because White’s e-pawn stays on e3 rather than e2, the f-pawn can advance without leaving e4 weak. Meanwhile Black has not yet committed the king’s bishop, so mistimed …dxc4 can leave the queenside under-defended.

Game Reference

[[Pgn|d4|d5|c4|e6|Nc3|c6|e3|Nf6|Nf3|Nbd7|Qc2|Bd6|Bd3|O-O|O-O|dxc4|Bxc4|b5|Be2|Bb7|e4|e5|Rd1|Qe7|Bg5|Rfe8|d5|a6|dxc6|Bxc6|Nh4|g6|Nd5|Bxd5|Rxd5|Qe6|Rad1|Be7|Nf3|Rac8|Qb1|Nxd5|Rxd5|Bxg5|Nxg5|Qc6|Qd1|Nb6|Rd6|Qc5|h4|| ]]

Beliavsky–Kramnik, Linares 1993. Beliavsky demonstrated the power of the quick e3-e4 break, culminating in a pawn-up endgame he duly converted.

Fun Fact

Alexander Beliavsky is one of the few players to defeat four World Champions—Karpov, Kasparov, Kramnik, and Anand—while employing a wide opening repertoire. His quiet 4.e3 system reflects his broader strategic style: solid yet poised for dynamic central expansion.