Four Knights: Scotch, 4...exd4 5.Nxd4 Bb4

Four Knights: Scotch, 4...exd4 5.Nxd4 Bb4

Definition & Move-order

The line arises from the Four Knights Game when White steers the play into Scotch-type structures with an early d4. The exact sequence is:

1. e4 e5 2. Nf3 Nc6 3. Nc3 Nf6 4. d4 exd4 5. Nxd4 Bb4

After Black’s fifth move the bishop pins the knight on c3 and puts pressure on the e4–square, introducing independent strategic and tactical motifs compared with the pure Scotch Game or the quieter Four Knights lines.

Strategic Themes

• Central Tension: The exchange on d4 removes one pawn but leaves both sides fighting for the remaining central pawn majority. Black hopes to prove that White’s knight on d4 is an over-extended target.
• Pin on c3: …Bb4 pinning the knight creates latent pressure against e4. If White ever plays 6. Nxc6 Black can respond …bxc6 opening the b-file, or capture on e4 in some lines.
• Rapid Development: Both sides have all four minor pieces out by move five; the question becomes how to harmonize rooks and queens while coping with the tactical possibilities.
• Imbalanced Pawn Structures: If White exchanges on c6 or Black plays …Nxe4, pawn formation transforms and long-term plans change dramatically (isolated d-pawn vs. hanging pawns, or pawn majority on the queenside).

Theoretical Status

While not the absolute main line of the Four Knights, 5…Bb4 is a fully respectable choice used by strong grandmasters as a low-maintenance way to equalise. Modern engines rate the position close to equality, but White keeps a pleasant initiative if well prepared.

Main Branches after 5…Bb4

1. 6. Nxc6 bxc6 7. Bd3 – Solid, aiming for rapid O-O and eventual f4 break.
2. 6. Nf5 – The Center Fork Trick motif; White hits g7 and sometimes picks up the bishop pair.
3. 6. Be2 Nxe4 7. O-O – A sharp line where White gambits a pawn for lead in development.
4. 6. Bg5 – Pins the knight on f6, preparing to undermine Black’s centre after an eventual Nd5.

Historical & Notable Games

• Rubinstein – Důras, San Sebastián 1912: a textbook demonstration of converting the bishop pair after 6. Nxc6.
• Kasparov – Kamsky, Dortmund 1992: illustrates the dynamic 6. Be2 line where White sacrificed a pawn for a lasting initiative.
• Carlsen – Vachier-Lagrave, London 2012: modern treatment with early 6. Bg5, ending in a well-fought draw.

Typical Tactical Motifs

• Center Fork Trick: 6. Nf5 can threaten Nd5, hitting c7 and e7 simultaneously.
• Pin & Skewer: …Bb4-bxc3 may double White’s pawns, creating long-term targets on the c-file.
• Pawn Sacrifice on e4: After 6. Be2 Nxe4 7. O-O Black’s knight can become trapped if not handled precisely.

Example Position to Visualise

After the basic moves the board (White to move) looks like this:
White must now choose between 6. Nxc6, 6. Be2, 6. Bg5, or 6. Nf5.

Plans for Each Side

• White:
  • Maintain central space with c2-c3 and f2-f3/f4.
  • Castle kingside quickly; aim rooks at the d- and e-files.
  • If possessing the bishop pair, keep the position open.
• Black:
  • Pressure e4 through the c6-knight, f6-knight and b4-bishop.
  • Consider …d5 break to free the game and activate the dark-square bishop.
  • If doubled c-pawns arise for White, target them with …Qc7 and rook lifts.

Interesting Facts & Anecdotes

• The entire sequence up to 5…Bb4 was once considered “automatic” in the pre-engine era; many club players rattled it off without detailed preparation, only to find themselves in hot water after © modern novelties.
• The line helped shape Akiba Rubinstein’s early reputation as an end-game virtuoso—his win against Důras is a model for exploiting the bishop pair.
• Despite its sedate look, Stockfish evaluation can swing over a pawn in a single move if either side mishandles the …Nxe4 tactics.

Why Add It to Your Repertoire?

For Black, 5…Bb4 is a neat, theory-light antidote to the Scotch Four Knights—far less explored than the symmetrical 5…Bb4 or 5…Bc5 of related openings. For White, knowing the critical continuations keeps the initiative alive and prevents Black from equalising effortlessly.

Further Study

• Chapter on the Scotch Four Knights in Play the Open Games as Black by John Emms.
• Chessable course “Master the Four Knights Game” for interactive drilling of tactical motifs.
• Database search of recent elite games (2018-2023) to see modern move orders and novelties.