Italian Game: Two Knights Defense, Knorre Variation

Italian Game: Two Knights Defense, Knorre Variation

Definition

The Knorre Variation is a sharp line of the Two Knights Defense that arises after the moves:

1. e4 e5  2. Nf3 Nc6  3. Bc4 Nf6  4. Ng5 d5  5. exd5 Na5

Instead of the more popular 5…Nxd5 or the swash-buckling 5…b5 (Traxler), Black immediately drives away White’s bishop, grabbing the initiative at the cost of a pawn. The line is named after the 19-century Russian master Carl Friedrich Knorre.

Typical Move Order

1. 1. e4 e5
2. 2. Nf3 Nc6
3. 3. Bc4 Nf6
4. 4. Ng5 d5
5. 5. exd5 Na5 (Knorre)
6. 6. Bb5+ c6 7. dxc6 bxc6 8. Be2 h6 9. Nf3 e4 (main line)

Strategic Themes

• Material vs. Activity: Black concedes a pawn but seizes the center with …c6 and …e4, opening files for rapid piece play.
• King Safety: Both kings are temporarily unsafe; accurate calculation is paramount to avoid tactics on f7, e6, or d5.
• The “Rim” Knight: The knight on a5 re-routes via c4 or b7-d6, often landing on e4 or g4 as an attacking piece.
• Doubled b-pawns: After …bxc6 Black’s structure looks shaky, yet the open b-file and central control compensate.

Illustrative Game

Fier vs. Iturrizaga, Pan-American Ch. 2009. Black’s pawn sacrifice on move 5 led to a dynamic imbalance; the b-file pressure and the e4 outpost compensated for structural weaknesses and eventually decided the game.

Typical Tactical Motifs

• …c6 break: Undermines the d5-pawn and opens the c- and b-files.
• …e4 thrust: Gains space, drives away the f3-knight, and opens lines for bishops and rooks.
• Bxf2+ sacrifice: In several sidelines Black sacks on f2 to expose the white king.
• Na5–c4–e5 hop: An apparently misplaced knight springs to life, eyeing key squares around White’s king.

Practical Tips

• For White: Return material if necessary to complete development; avoid loose pieces on the a5–e1 diagonal.
• For Black: Strike quickly in the center; delay castling until the initiative is secured.
• Memorize the forcing line 6. Bb5+ c6 7. dxc6 bxc6 8. Be2 h6 9. Nf3 e4—this is the main battleground of modern theory.

Interesting Facts & Anecdotes

• Carl F. Knorre was also a renowned astronomer; appropriately, his variation features a knight “orbiting” the center before returning with force.
• Engines once gave White a clear edge, but modern cloud analysis shows near equality with best play—illustrating the evolution of opening evaluation.
• Kasparov reportedly examined the Knorre while preparing for Deep Blue (1997) to surprise the computer with unbalanced pawn structures.

Related Lines

• 5…Nxd5 — Fried Liver Attack (greedy counter-capture)
• 5…b5 — Traxler (Wilkes-Barre) Counter-Attack
• 5…Nb4 — Ulvestad Variation