Sicilian: Loewenthal, 5.Nb5
Sicilian Defence: Löwenthal Variation (5.Nb5)
Definition
The Löwenthal Variation is a sub-line of the Sicilian Defence that arises after the moves:
1. e4 c5 2. Nf3 d6 3. d4 cxd4 4. Nxd4 Nf6 5. Nb5.
With 5.Nb5 White immediately jumps a knight into Black’s camp, attacking the d6-pawn and eyeing the sensitive d6–c7 squares. The move outlines a flexible, strategic system that differs from the sharper Open Sicilian main lines like the Najdorf (5...a6) or Dragon (5...g6).
Typical Move Order
The basic branching point occurs after 5.Nb5:
- 5…a6 6.N5c3 e6 leads to a tabiya that resembles the Classical Sicilian with the knight rerouted.
- 5…Nc6 6.N1c3 a6 7.Na3 keeps pressure on c4 and d5 squares.
- 5…e6 transposes into Scheveningen-style structures, but the knight on b5 annoys Black.
Strategic Themes
White’s 5.Nb5 has three major strategic goals:
- Pressure on d6: The advance …d6 is the cornerstone of many Sicilians; forcing its protection cramps Black’s position.
- Control of d5: By removing the c6-knight (in some lines Bxb5 or Nd6+), White can make …d5 harder to achieve.
- Flexible development: White can choose setups with c4 (English Attack-style), Be2 & 0-0 (quiet), or even a quick f4 (aggressive).
Historical Background
The line is named after Johann Jakob Löwenthal (1810-1876), a Hungarian-British master who championed the idea of early Nb5 in the mid-19th century. Although overshadowed by Morphy and Staunton in his own era, Löwenthal’s contributions to early Sicilian theory were substantial. His games reveal the embryonic stages of modern anti-Najdorf ideas.
Modern Usage
While less popular than the Najdorf or Sveshnikov, 5.Nb5 remains a practical weapon at all levels because it sidesteps enormous theoretical jungles and often leads to positions where understanding trumps memorization. Grandmasters such as Sergei Rublevsky and Baadur Jobava have employed it to avoid heavily analysed Najdorf territory.
Illustrative Game
Rublevsky – Svidler, Russian Ch., Moscow 2007. White’s Nb5 pressured d6 early; later he castled long and built a kingside attack, underscoring the line’s positional flexibility.
Theoretical Status
Engines give Black full equality with accurate play, but the paths are less forcing than in mainline Najdorf branches. Current theory views 5…a6 and 5…e6 as most critical; 5…Nc6 is playable but grants White easier development after c4.
Typical Plans for Each Side
- White
- Castle long (0-0-0) and launch g- and h-pawns down the kingside.
- Play c4 & Nc3-d5 to clamp central breaks.
- Use a timely Bxf6 or Nd6+ to damage Black’s pawn structure.
- Black
- Kick the knight with …a6 and aim for …b5-b4 to gain queenside space.
- Break with …d5 once pieces are harmonised, equalising central influence.
- Exploit the temporary awkwardness of White’s b5-knight and c3-knight overlap.
Famous Anecdote
Grandmaster Ljubomir Ljubojević reportedly adopted 5.Nb5 during a blitz session because he “forgot his Najdorf file at home.” He proceeded to score a flurry of wins, quipping that “sometimes forgetting theory is the best theory.”
Interesting Facts
- The move 5.Nb5 indirectly provoked one of the earliest theoretical footnotes on move orders: some Najdorf players insert 5…a6 first in virtually every line to sidestep it.
- World Champion Anatoly Karpov used the 5.Nb5 idea in simultaneous exhibitions to avoid giving away opening secrets while still playing principled chess.
- The line’s ECO code is B32, but some databases list early deviations under B33 when Black chooses Scheveningen-style …e6 setups.
Practical Tips
For tournament players choosing 5.Nb5:
- Memorise only a few key branching points (5…a6, 5…e6, 5…Nc6).
- Rehearse typical knight manoeuvres: Nb5-c3-d5 and Nb5-d6+.
- Be aware that after 5…a6 6.Nd4 Black can transpose into standard Scheveningen lines; keep your repertoire cohesive.