Chess Openings Lab
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Sicilian Defense: Hyperaccelerated Pterodactyl

The Hyperaccelerated Pterodactyl is 1.e4 c5 2.Nf3 g6 3.d4 Bg7, where Black lets White take on c5 and develops the bishop instead. Black plans ...Qa5+ to win the pawn back with active pieces, while White aims to keep the extra space or push d5.

Moves
1.e4 c5 2.Nf3 g6 3.d4 Bg7
ECO
B27
Engine
+0.72 · a slight edge for White (Stockfish 17.1, depth 20)
Played
1,356 games in our lichess sample
White scores
49.0%

Key ideas for both sides

White

  • 4.dxc5 Qa5+ 5.c3 Qxc5 6.Na3 brings the knight toward b5 and c4 with tempo on the queen.
  • Be3 after the queen lands on c5 gains more time and helps White develop quickly.
  • 4.d5 locks the center and gives a Benoni-style space edge after Nc3 and Bc4.
  • 4.c3 keeps the center; after ...cxd4 cxd4 d5, e5 and Qb3 hit the b7 pawn.

Black

  • After dxc5, ...Qa5+ and ...Qxc5 regain the pawn and put the queen on an active square.
  • Follow with ...d6, ...Nc6 and ...Nf6, as the queen steps back to a5 when hit.
  • Against d5, play ...Nf6, ...d6 and ...O-O, then ...Na6 and ...Nc7 to support ...b5.
  • The g7 bishop is the heart of the setup. Keep the long diagonal open.

Plans and pawn structure

The bishop on g7 hits d4 at once, so White must react. Taking on c5 leads to a race of tempi: Black's queen regains the pawn, but White develops with Na3, Be3 and Nb5 ideas. Pushing d5 gives a closed center where White has space and Black plays ...b5 and ...e6 breaks. With c3, the game becomes an Alapin-type center where Black hits with ...d5 and White pushes e5 and uses Qb3 against b7.

Where the engine's main line heads: Dragon structure: ...d6 and ...g6. The Dragon structure: ...d6 and ...g6 with the bishop on g7 aimed down the long diagonal at White's queenside.

What the engine plays from here

Stockfish 17.1 at depth 20 rates the position +0.72: a slight edge for White. Its three top choices for White:

  1. +0.72 4.dxc5 Qa5+ 5.c3 Qxc5 6.Na3 d6
  2. +0.68 4.d5 Nf6 5.Nc3 d6 6.Bc4 O-O
  3. +0.52 4.c3 cxd4 5.cxd4 d5 6.e5 a6

Pawns, from White's side.

How it scores on lichess

1,356 rated lichess games reached this position; White scored 49.0%.

under 120058.1%
1200–159950.2%
1600–199950.3%
2000 and up44.2%

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

Where it goes next

  • Sicilian, Unpin4.Nc3 · rare
  • Hyperaccelerated Pterodactyl, Exchange Variation4.dxc5 · rare

How to play against it

With White, 4.dxc5 is the most testing: answer ...Qa5+ with c3 and then use Na3 and Be3 to gain time on the queen. Do not try to keep the pawn with b4, which loosens the queenside. If you prefer a closed game, d5 is a calmer choice.

Questions

What are the moves of the Sicilian Defense: Hyperaccelerated Pterodactyl?

The Sicilian Defense: Hyperaccelerated Pterodactyl starts 1.e4 c5 2.Nf3 g6 3.d4 Bg7. Its ECO code is B27.

Is the Sicilian Defense: Hyperaccelerated Pterodactyl good for Black?

Stockfish 17.1 rates the position +0.72 at depth 20, which is a slight edge for White. In 1,356 lichess games from our sample, White scored 49.0%. A tricky line for Black players who know the ...Qa5+ ideas; White does well with fast development after taking on c5.

What is the main idea of the Sicilian Defense: Hyperaccelerated Pterodactyl?

Black uses the g7 bishop to hit d4 and allows dxc5, planning ...Qa5+ to regain the pawn. White can take and gain time against the queen, or push d5 for space.

What should White play next?

The engine's first choice is dxc5, with d5 and c3 close behind. 4.dxc5 grabs the pawn, and after ...Qa5+ c3 White develops with tempo on the queen.

Updated October 2026. Sources and method.