Chess Openings Lab
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Sicilian Defense: Smith-Morra Gambit Declined, Center Formation

The Center Formation is 3...e5, where Black declines the Smith-Morra by guarding the d4 pawn with another pawn. White wants Nf3 and cxd4 to break up Black's center, and Black aims for ...Nc6 and ...Nf6 with fast development after the exchanges.

Moves
1.e4 c5 2.d4 cxd4 3.c3 e5
ECO
B21
Engine
+0.03 · level (Stockfish 17.1, depth 20)
Played
642 games in our lichess sample
White scores
46.5%

Key ideas for both sides

White

  • Play 4.Nf3 to attack e5, then take on d4 with the c-pawn and recapture with the knight.
  • 4.Bc4 and Ng5 hit f7 at once; after ...d5 exd5, Black's knight goes to a5 to chase the bishop.
  • After exchanges on d4, a ...Bb4 pin is common, so be ready with Bd3 or Bd2.

Black

  • Answer Nf3 with ...Nc6 and, after the exchanges, ...Nf6 and ...Bb4 to pressure e4.
  • Against Bc4 and Ng5, strike with ...d5 and use ...Na5 to win the bishop pair.
  • After cxd4 exd4, ...Bc5 develops with pressure on d4 and prepares fast castling.

Plans and pawn structure

After the trades on d4 the position becomes open with nearly symmetrical development. Black gets easy piece play with ...Nf6, ...Bb4 or ...Bc5 and castling, and White's e4 pawn can become a target. White wants Nc3, Bd3 and castling, using the d5 square and the e-file. Neither side has weaknesses, so active pieces decide. Black should castle before pushing for more, and White should not let the e4 pawn become a fixed target.

Where the engine's main line heads: Black has an isolated queen pawn. Black has an isolated d-pawn: nothing on the c- or e-file to support it.

What the engine plays from here

Stockfish 17.1 at depth 20 rates the position +0.03: level. Its three top choices for White:

  1. +0.03 4.Nf3 Nc6 5.cxd4 exd4 6.Nxd4 Nf6
  2. −0.07 4.Bc4 Nf6 5.Nf3 Nc6 6.Ng5 d5
  3. −0.11 4.cxd4 exd4 5.Nf3 Bc5 6.Nxd4 Nf6

Pawns, from White's side.

How it scores on lichess

642 rated lichess games reached this position; White scored 46.5%.

1200–159950.3%
1600–199947.6%
2000 and up38.8%

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

How to play against it

As White, do not leave the d4 pawn alone: play Nf3 and cxd4 to clear the center. Develop quickly and watch for ...Bb4 pins on c3. Do not chase the e5 pawn with a knight before you have castled. Castling early keeps your king out of the tactics on the e-file.

Questions

What are the moves of the Sicilian Defense: Smith-Morra Gambit Declined, Center Formation?

The Sicilian Defense: Smith-Morra Gambit Declined, Center Formation starts 1.e4 c5 2.d4 cxd4 3.c3 e5. Its ECO code is B21.

Is the Sicilian Defense: Smith-Morra Gambit Declined, Center Formation good for Black?

Stockfish 17.1 rates the position +0.03 at depth 20, which is level. In 642 lichess games from our sample, White scored 46.5%. A low-risk way to decline the gambit for Black players who like open, equal positions.

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

Black refuses the second pawn and props up d4 with ...e5. White breaks the chain with Nf3 and cxd4, and the game becomes an open, balanced position.

What should White play next?

The engine's first choice is Nf3, with Bc4 and cxd4 close behind. 4.Nf3 attacks e5 right away, forcing Black to defend it before the center opens.

Updated October 2026. Sources and method.