Chess Openings Lab
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Sicilian Defense: Smith-Morra Gambit Accepted, Kan Formation

The Kan Formation of the Smith-Morra is 4...e6 5.Nf3 a6, where Black stops knight jumps to b5 before developing. White develops with Bf4, Bd3 or Be3 and looks for e5, while Black aims for ...d6, ...Nc6 and ...Nf6 with an extra pawn.

Moves
1.e4 c5 2.d4 cxd4 3.c3 dxc3 4.Nxc3 e6 5.Nf3 a6
ECO
B21
Engine
−0.10 · level (Stockfish 17.1, depth 20)
Played
457 games in our lichess sample
White scores
49.8%

Key ideas for both sides

White

  • 6.Bf4 eyes d6 and prepares e5; follow with Rc1 and Bd3 to use the c-file.
  • Bd3 and O-O, then e5 against ...d6, open lines while Black's kingside is undeveloped.
  • Be3 with h3 and Rc1 is a slower plan that rules out ...Ng4 and keeps the bishop safe.

Black

  • Play ...d6 to keep e5 under control, and answer e5 with ...d5 for a French-type center.
  • Develop with ...Nc6, ...Nf6 and ...Be7, then castle; the a6 pawn already stops Nb5.
  • Use ...b5 later to gain queenside space and prepare to put the c8 bishop on the long diagonal.

Plans and pawn structure

Black's ...a6 shuts out the knight jump to b5, so White's pieces need other routes. White's plan is Bf4 or Bd3, castling, Rc1 and e5 to cramp Black. Black wants ...d6, ...Nf6 and ...Be7, then ...b5 to grab queenside space and free the c8 bishop. If Black meets e5 with ...d5, the center locks and White's space must balance the missing pawn.

What the engine plays from here

Stockfish 17.1 at depth 20 rates the position −0.10: level. Its three top choices for White:

  1. −0.10 6.Bf4 d6 7.e5 d5 8.Rc1 Nc6
  2. −0.27 6.Bd3 d6 7.O-O Nf6 8.e5 dxe5
  3. −0.34 6.Be3 Nc6 7.h3 d6 8.Rc1 Nf6

Pawns, from White's side.

How it scores on lichess

457 rated lichess games reached this position; White scored 49.8%.

1200–159942.4%
1600–199951.9%
2000 and up49.7%

Light: White wins. Grey: draws. Dark: Black wins. About the sample.

How to play against it

As White, avoid quiet setups that let Black finish development. Use Bf4 against d6 and push e5 at the right moment. Do not aim knights at b5, because the a6 pawn covers that square. Instead, route pieces through f4, d3 and c1, and keep e5 as your main lever.

Questions

What are the moves of the Sicilian Defense: Smith-Morra Gambit Accepted, Kan Formation?

The Sicilian Defense: Smith-Morra Gambit Accepted, Kan Formation starts 1.e4 c5 2.d4 cxd4 3.c3 dxc3 4.Nxc3 e6 5.Nf3 a6. Its ECO code is B21.

Is the Sicilian Defense: Smith-Morra Gambit Accepted, Kan Formation good for Black?

Stockfish 17.1 rates the position −0.10 at depth 20, which is level. In 457 lichess games from our sample, White scored 49.8%. A practical setup for Black players who want to neutralize knight jumps, while White needs active bishop play to justify the pawn.

What is the main idea of the Sicilian Defense: Smith-Morra Gambit Accepted, Kan Formation?

Black plays ...e6 and ...a6 to take b5 and d5 away from White's knights. White develops the c1 bishop to f4 or e3 and looks for e5 to cramp Black.

What should White play next?

The engine's first choice is Bf4, with Bd3 and Be3 close behind. 6.Bf4 develops with a direct look at d6, getting ready for e5 and a rook on c1.

Updated October 2026. Sources and method.