Chess Openings Lab
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Vienna Game: Mengarini Variation

The Mengarini Variation is 2...Nf6 3.a3, a quiet pawn move that takes b4 away from Black's bishop. White wants a reversed Sicilian-style game with a later b4, while Black can grab the center with ...d5 or develop with ...Bc5.

Moves
1.e4 e5 2.Nc3 Nf6 3.a3
ECO
C26
Engine
−0.21 · level (Stockfish 17.1, depth 20)
Played
542 games in our lichess sample
White scores
51.8%

Key ideas for both sides

White

  • a3 means ...Bb4 is never possible, so the c3 knight always guards e4 and d5.
  • After ...Bc5, play Nf3, h3 and Bc4, then d3 and castling for a solid setup.
  • Against ...d5, take with exd5 and after ...Nxd5 hit the e5 pawn with Qh5.
  • Expand with b4 later to gain space and push back a bishop on c5.

Black

  • ...Bc5 is the engine's first choice, putting the bishop on the active diagonal before b4 comes.
  • ...d5 is a direct answer: White's a3 is slow, so Black takes central space right away.
  • After ...Nc6 and Nf3, push ...d5; after Bb5, the knight on e4 lands with tempo.
  • Castle short with ...O-O and add ...c6 and ...d6 to build a solid center.

Plans and pawn structure

White's a3 is a slow but useful move: it rules out pins with ...Bb4 and prepares b4 for queenside space. White develops with Nf3, Bc4, d3 and h3, then plays for b4 or a central d4. Black has time: ...Bc5, ...d6, ...c6 and castling build a sturdy center, and ...d5 is the freeing break. If Black opens with ...d5 at once, the game becomes an open fight around e5 and the d5 knight.

Where the engine's main line heads: Open game: e4 against e5. An open game: e4 against e5. Development, the f7 and f2 squares, and the d4 or d5 break are what count.

What the engine plays from here

Stockfish 17.1 at depth 20 rates the position −0.21: level. Its three top choices for Black:

  1. −0.21 3...Bc5 4.Nf3 d6 5.h3 O-O 6.Bc4
  2. −0.16 3...Nc6 4.Nf3 d5 5.Bb5 Nxe4 6.Nxe5
  3. −0.14 3...d5 4.exd5 Nxd5 5.Qh5 Nc6 6.Bb5

Pawns, from White's side.

How it scores on lichess

542 rated lichess games reached this position; White scored 51.8%.

under 120047.9%
1200–159952.1%
1600–199954.1%

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

How to play against it

As Black, use the time White spent on a3. Play ...Bc5 or ...d5 and develop quickly, then castle short. Do not count on ...Bb4 pins in this line, and keep the bishop ready to retreat to a7 when White pushes b4.

Questions

What are the moves of the Vienna Game: Mengarini Variation?

The Vienna Game: Mengarini Variation starts 1.e4 e5 2.Nc3 Nf6 3.a3. Its ECO code is C26.

Is the Vienna Game: Mengarini Variation good for White?

Stockfish 17.1 rates the position −0.21 at depth 20, which is level. In 542 lichess games from our sample, White scored 51.8%. A quiet sideline for White players who want to avoid theory, but Black gets an easy, equal game.

What is the main idea of the Vienna Game: Mengarini Variation?

White spends a move on a3 to stop ...Bb4 and prepare b4 for queenside space. Black uses the time to develop with ...Bc5 or strike with ...d5.

What should Black play next?

The engine's first choice is Bc5, with Nc6 and d5 close behind. ...Bc5 develops the bishop to its best square before White's b4 can chase it.

Updated October 2026. Sources and method.