Alekhine: Modern, Flohr, 6.O-O

Alekhine Defence: Modern Variation, Flohr Line (6.O-O)

Definition

The Alekhine Defence begins with 1. e4 Nf6, inviting White to overextend the centre so that Black can later counter-attack. The Modern Variation (characterised by …g6 and …Bg7) is one of Black’s most flexible set-ups. When White castles short on move six—6.O-O after 5…Nb6—following the practice of the great Czech grandmaster Salo Flohr, we arrive at the Flohr Line. The full name therefore reads: “Alekhine Defence, Modern Variation, Flohr Line (6.O-O).”

Typical Move Order

A very common sequence is:

e4 Nf6
e5 Nd5
d4 d6
Nf3 g6
Bc4 Nb6
O-O …

White occupies the centre with pawns on e5 and d4, develops naturally, and preserves the bishop pair. Black fianchettoes the king’s bishop to pressure the e5-pawn and prepares typical counter-play with …dxe5, …c5, or …Bg4.

Strategic Ideas

White aims for rapid development and often follows with Re1, Bb3, c4 and Nc3, building a broad centre.
Black relies on piece pressure rather than immediate pawn breaks:
- …Bg7 targets e5 and may be followed by …Nc6 or …dxe5.
- …c5 strikes at d4, forcing concessions or exchanges.
- …Bg4 pins the f3-knight, undermining d4 and e5 simultaneously.
Because the queens often remain on the board, middlegames can become highly tactical; yet if the centre stabilises, Black enjoys solid, hedgehog-like positions.

Critical Continuations

After 6…Bg7 7.Bb3 O-O the main branching points are:

8.Qe2 — classical development, eyeing the e-file.
8.Re1 — immediate central reinforcement, sometimes preparing c4.
8.a4 — discouraging …a5 and fixing the b6-knight.
8.c3 — a modest move that underpins d4 and prepares a later d4-d5 pawn advance.

Historical & Practical Significance

Salo Flohr employed this set-up in the 1930s, when the Alekhine Defence was still relatively new. His games showed that simple development and castling give White a healthy, durable centre without risking the over-extension that Alekhine himself had hoped to provoke.

The line remains topical: elite players choose it when they want to avoid heavy theoretical duels in sharper lines such as the Four-Pawn Attack. Notable modern practitioners include Vishy Anand and Ian Nepomniachtchi, who have used it as White to maintain a small but enduring edge.

Illustrative Games

Flohr – Eliskases, Bad Neuendorf 1937 Flohr demonstrated the strength of Bb3 followed by c4 and Nc3, squeezing Black’s queenside and converting a pleasant advantage.
Anand – Ivanchuk, Dortmund 1997 Anand’s 8.Qe2 kept flexible options. After careful manoeuvring, White broke through on the kingside with f4-f5.
Nepomniachtchi – Giri, Candidates 2020 A modern example showing the topical 8.a4. The game ended in a draw, but only after Black defended an uncomfortable position for 60 moves.

Interesting Facts

The name “Modern” is a bit misleading—this set-up actually dates back to the 1920s. The term distinguished it from the “Classical” Alekhine lines with …dxe5 and …Bg4.
Because the move 6.O-O is such a natural developing choice, some opening manuals list the line simply as “Alekhine: 4…g6” without further subdivision, but advanced databases still honour Flohr’s contribution.
World Champion Magnus Carlsen has tried the Black side of the Modern Variation repeatedly, trusting its solidity in rapid and blitz formats.

Summary

The Flohr Line of the Modern Alekhine offers White a sound, strategically rich position with minimal risk, while Black receives the dynamic counter-punching chances characteristic of the Alekhine Defence. Its balance of safety and complexity explains why it remains a popular weapon from club level to top grandmaster play.