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

The Fianchetto Defense of the Smith-Morra is 4...g6, where Black puts the bishop on g7 to cover the long diagonal and the c3 knight. White wants Nf3, Bc4 and e5 to shut out that bishop, while Black aims for ...Nc6, ...Nh6 and short castling.

Moves
1.e4 c5 2.d4 cxd4 3.c3 dxc3 4.Nxc3 g6
ECO
B21
Engine
0.00 · level (Stockfish 17.1, depth 20)
Played
574 games in our lichess sample
White scores
52.1%

Key ideas for both sides

White

  • Play Nf3 and Bc4, then e5 to blunt the g7 bishop and take f6 from Black's knight.
  • With e5 in, castle and use the f7 target: Bc4 and a knight on g5 put pressure on it.
  • Keep e5 supported with Bf4 or Qe2 so Black cannot break it easily.

Black

  • Develop with ...Bg7 and ...Nc6, then ...Nh6, since e5 takes f6 from the g8 knight.
  • Castle short quickly; the g7 bishop guards the king and eyes e5 and c3.
  • Hit e5 with ...d6 or ...f6 once the king is safe, opening lines for the bishop.

Plans and pawn structure

The key fight is over e5. If White gets e5 in safely, the g7 bishop stares at a wall and Black's knight must go to h6. Black then castles and undermines e5 with ...d6 or ...f6, after which the bishop and the rooks become active. White uses Bc4, castling and Qe2 or Bf4 to keep e5 supported. The extra pawn gives Black a long-term edge if the position opens on Black's terms.

What the engine plays from here

Stockfish 17.1 at depth 20 rates the position 0.00: level. Its three top choices for White:

  1. 0.00 5.Nf3 Bg7 6.Bc4 Nc6 7.e5 Nh6
  2. −0.01 5.e5 Bg7 6.Nf3 Nh6 7.Bc4 O-O
  3. −0.03 5.Bc4 Nc6 6.Nf3 Bg7 7.e5 Nh6

Pawns, from White's side.

How it scores on lichess

574 rated lichess games reached this position; White scored 52.1%.

1200–159950.6%
1600–199952.2%
2000 and up51.7%

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

How to play against it

As White, play Nf3, Bc4 and e5 without delay to cramp the g7 bishop. Castle before starting tactics. Do not push e5 before it has support, because ...d6 can then hit it at once. If Black castles early, Qe2 and a rook on d1 keep e5 well supported.

Other lines with this name

The lichess opening list also files these lines under the same name, though they reach a different position: 1.e4 c5 2.d4 cxd4 3.c3 dxc3 4.Nxc3 Nc6 5.Nf3 g6; 1.e4 c5 2.d4 cxd4 3.c3 dxc3 4.Nxc3 Nc6 5.Nf3 d6 6.Bc4 g6; 1.e4 c5 2.d4 cxd4 3.c3 dxc3 4.Nxc3 d6 5.Nf3 g6.

Questions

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

The Sicilian Defense: Smith-Morra Gambit Accepted, Fianchetto Defense starts 1.e4 c5 2.d4 cxd4 3.c3 dxc3 4.Nxc3 g6. Its ECO code is B21.

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

Stockfish 17.1 rates the position 0.00 at depth 20, which is level. In 574 lichess games from our sample, White scored 52.1%. A sound, low-theory choice for Black players who like fianchetto setups, while White must play e5 at the right moment.

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

Black fianchettoes the bishop to guard the king and hit the c3 knight. White answers with e5 to shut the bishop out and take f6 away from Black's knight.

What should White play next?

The engine's first choice is Nf3, with e5 and Bc4 close behind. 5.Nf3 develops and prepares e5, so Black's g8 knight will have to use h6 instead of f6.

Updated October 2026. Sources and method.