Openings · A01

Larsen's Opening

1.b3 — the bishop goes to b2 on move two and looks down the long diagonal for the rest of the game.

1.b3played as White

Play it through on the board below, and 8 moves into the main line.

Practise the line

You play White; the other side answers on its own. Nothing here is saved or graded. The line runs on past the moves that define the opening and into the main line, because two moves is not a drill.

8
7
6
5
4
3
2
a1
b
c
d
e
f
g
h
Your move 1 of 50/5
  1. 1.b3e5
  2. 2.Bb2Nc6
  3. 3.e3Nf6
  4. 4.Bb5Bd6
  5. 5.Nf3

Your move. Drag a piece, or tap it and then its square.

The idea

Fianchetto first, decide about the centre later. The bishop on b2 hits e5 and g7, and White follows with e3, Nf3 and either f4 or c4 depending on what Black has built.

It is a genuine opening with a genuine drawback: it does nothing about the middle of the board, and 1…e5 followed by …Nc6 and …d5 gives Black a big centre for free. The bishop has to be worth the pawns it is not putting there.

Common mistakes

Three that come up again and again below master level: named traps and the errors every coach corrects.

Hitting the centre before castling

After 5…Qh4+
  1. 1.
  2. 2.
  3. 3.
  4. 4.
  5. 5.
The mistake
Playing f4 to challenge the big black centre with the king still on e1.
Why it costs
The f-pawn's departure opens the e1–h4 diagonal, and …Qh4+ arrives with tempo before White has castled. Black gets to develop with checks. The engine still calls it about level, so the cost is time rather than material, but time is the one thing a slow opening cannot afford.
Instead
Nf3 first, and f4 later if at all. Against a strong centre the useful moves are the ones that hit it without loosening the king.

Putting a pawn on the bishop's diagonal

After 7.c3
  1. 1.
  2. 2.
  3. 3.
  4. 4.
  5. 5.
  6. 6.
  7. 7.
The mistake
Playing d4 and c3 in front of the bishop that the whole opening was built round.
Why it costs
d4 and c3 are both on the a1–h8 diagonal. The bishop on b2 was the reason for 1.b3, and it now sees the back of two of its own pawns while Black has an ordinary, comfortable Queen's-Gambit-style position.
Instead
Keep the d-pawn on d3 and fight for e5 with f4 or with pieces. The pawn goes to d4 when it wins that square rather than when it blocks the bishop.

Opening lines beside your own king

After 10.f4
  1. 1.
  2. 2.
  3. 3.
  4. 4.
  5. 5.
  6. 6.
  7. 7.
  8. 8.
  9. 9.
  10. 10.
The mistake
Playing f4 with the king uncastled and Black's rooks already connected — Larsen against Spassky, 1970.
Why it costs
Spassky answered 10…Ng4, met 11.g3 with 11…h5, and the h-pawn arrived with the file opening in front of it. The game finished 14…Rh1 and mate on move seventeen, and White never made a move that looked like a blunder.
Instead
Castle, or at least play h3 and Nc3 before touching the f-pawn. In this opening the king lives in the middle longer than usual, so lines have to stay shut longer than usual too.

In real games between beginners

  • 1 in 67games end with White giving checkmate by move 15. In all openings: 1 in 33.
  • 1 in 45games end with White getting checkmated by move 15. In all openings: 1 in 54.

From 3,600 Lichess games in this opening between players rated under 1200, blitz and slower, September 2026. How we counted.

What the engine says

After 1.b3, these are Black's six best moves according to Stockfish, with the bar showing Black's chance of winning. The whole list sits within 4 percentage points of win chance: none of them is a mistake, and the choice is about the positions you want to play.

  1. e5-0.2
  2. Nf6-0.0
  3. c5+0.0
  4. g6+0.1
  5. d5+0.2
  6. Nc6+0.2

The engine's main line from e5: e5 Bb2 Nc6 e3 d5 Bb5 Bd6 Nf3.

Stockfish 18, depth 24. Scores are in pawns from White's side. Another engine or depth will move individual numbers a little; the picture does not change. How we check.

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