Sicilian: Prins (Moscow), 5...e5 6.Nb3

Sicilian: Prins (Moscow), 5...e5 6.Nb3

Definition

The line known as the Prins Variation of the Moscow (3.Bb5+) System in the Sicilian Defence arises after the moves 1.e4 c5 2.Nf3 d6 3.Bb5+ Bd7 4.Bxd7+ Qxd7 5.c4 e5 6.Nb3. It is named after Dutch Grandmaster Lodewijk Prins, who championed the early 5.c4 idea, and it appears under ECO code B51.

Typical Move-order

One of the most common sequences is:

1. e4  c5
2. Nf3  d6
3. Bb5+  Bd7 (the Moscow System)
4. Bxd7+  Qxd7
5. c4  (the Prins set-up, aiming for a Maroczy Bind)
6. …e5  (Black prevents d4 and grabs central space)
7. Nb3  (the knight re-routes toward d5 and c3)

Strategic Themes

• Maroczy-flavoured Bind: By playing 5.c4 White clamps down on …d5, hoping for long-term spatial pressure.
• Black’s central expansion: The immediate 5…e5 challenges White’s setup, gains space, and fixes the pawn on e4, but leaves the d5-square permanently weak.
• Outpost warfare: After 6.Nb3, the knight often lands on d5, while Black seeks counterplay on the dark squares with …g6, …Bg7 and possibly …f5.
• Flexible pawn breaks: White can prepare f2-f4 or b2-b4; Black usually looks for …b5 or …f5 depending on where White castles.
• Piece imbalances: Because White traded the light-squared bishop early, control of the light squares (especially d5 and e4) becomes a critical theme.

Historical Development

Lodewijk Prins began experimenting with 5.c4 in the late 1940s, presenting an alternative to the standard 5.O-O lines. The move gained broader attention when Soviet players such as Yuri Averbakh and Efim Geller used it to sidestep heavy Sicilian theory. In modern times, it serves as a practical surprise weapon, occasionally adopted by elite grandmasters, including Vladimir Kramnik and Fabiano Caruana.

Illustrative Example

The following miniature game shows typical ideas for both sides:

Key motifs:

• White’s knight hops to d5 and f6 became a latent threat.
• Black’s …f5 break aimed for counterplay but weakened e6 & g6.
• The light-squared bishop trade meant Black’s dark-square play (…Bg7, …f5) was essential.

Key Ideas for Both Sides

• White
  • Occupy or blockade d5 with a knight or pawn.
  • Expand on the kingside with f2-f4 or queenside with b2-b4.
  • Avoid premature d2-d4; the thrust must be well prepared.
• Black
  • Counterattack on the dark squares with …g6, …Bg7, …f5.
  • Break the bind by timely …b5 or even …d5 when supported.
  • Exploit the absence of White’s light-squared bishop along the a7–g1 diagonal.

Interesting Facts & Anecdotes

• Lodewijk Prins defeated several Soviet masters with this line, adding to its “Moscow” nickname because so many Russian players had to face it during post-war events held in the USSR.
• Although 5.c4 scores well in databases (often over 55% for White), the immediate 5…e5 is statistically Black’s most combative answer.
• A quirky sideline is 6…f5!? known as the “Dutch-in-the-Sicilian”, echoing another opening associated with Prins.

At-a-Glance Summary

The Prins (Moscow) variation with 5…e5 6.Nb3 is a strategic battleground: White clamps down on d5 and maneuvers pieces patiently, while Black strikes back on the dark squares and looks to break the bind with pawn thrusts. Its relative rarity makes it an excellent surprise weapon for players who enjoy positional Sicilians with clear plans for both colours.