Slav: 4.e3 Bf5 5.Nc3 e6 6.Nh4 Bg4

Slav: 4.e3 Bf5 5.Nc3 e6 6.Nh4 Bg4

Definition

This line is a branch of the Slow Slav Defence that begins with the moves 1.d4 d5 2.c4 c6 3.Nf3 Nf6 4.e3 Bf5 5.Nc3 e6 6.Nh4 Bg4. After White’s provocative 6.Nh4, which attacks the bishop on f5, Black sidesteps by pinning the knight on f3 instead of retreating. The position remains solid and symmetrical, but both sides have early strategic commitments that shape the middlegame.

How It Is Used in Chess

• For Black, the 6…Bg4 pin aims to keep the c8-bishop active, postpone …h6 or …g5, and discourage White from playing g2–g4 or h2–h3 too freely.
• For White, 6.Nh4 fixes the f5-bishop and often prepares 7.f3 and 8.g4, grabbing space on the kingside at the cost of weakening the own king. Alternatively, White can simply exchange on f5 and claim the bishop pair.

Strategic Themes and Typical Plans

• Space vs. Structure: White can gain space on the kingside with g2–g4 and h2–h3, while Black relies on a rock-solid pawn chain (d5–c6–e6) and piece activity.
• The Light-Squared Bishops: Both bishops (on c1 and c8) often become powerful. If Black preserves the bishop with …Bh5 or …Bf5 later, Black keeps excellent control of the e4-square.
• Minor-Piece Imbalances: Exchanging on g4 can leave Black with doubled g-pawns; declining the exchange may drive the piece to h5 or f5 where it can be harassed again.
• Central Breaks: The thematic breaks …c5 or …e5 (for Black) and e4 or cxd5 (for White) decide when the struggle leaves the slow, manoeuvring phase.

Historical Significance

The Slow Slav (4.e3) was popularised in the 1920s and 30s by ex-world-champion Max Euwe. The specific 6…Bg4 variation became a low-maintenance “equaliser” in the repertoires of grandmasters such as Vassily Smyslov and later Vladimir Kramnik. Modern engines confirm its soundness, so it is still regularly seen in elite rapid and blitz events where Black wants a solid setup with clear plans and little theory to memorise.

Notable Games

1. Anand – Kramnik, Wijk aan Zee 1998 — Kramnik neutralised White’s kingside pawn storm and later broke with …c5, eventually winning a model endgame.
2. Hou Yifan – So Wesley, Biel 2016 — White’s ambitious 7.f3 and 8.g4 led to sharp play, but Black’s counter in the centre equalised efficiently.
3. Karpov – Smyslov, Moscow 1971 (training) — An early showcase of the line’s strategic richness; the game ended in a balanced queenless middlegame.

Illustrative Mini-PGN

The following snippet shows one of the most common continuations:

Interesting Facts & Anecdotes

• The move 6.Nh4 has been dubbed the “mosquito-jump” by some trainers, because it keeps buzzing around Black’s light-square bishop until it is swatted away.
• In online blitz, grandmasters sometimes meet 6.Nh4 with the cheeky 6…Be4?!, inviting 7.f3 Bg6 8.Nxg6 hxg6 when material is equal but Black gains the bishop pair; this sideline, though objectively inferior, is hard to refute quickly over the board.
• The entire 4.e3 Bf5 system is so solid that, according to database statistics, it is one of the very few queen-pawn openings in which Black scores almost 50 % at all rating levels above 2400.