Why White Plays b4
Tempo, deflection, the open b-file and the a3-f8 diagonal.
1. e4 e5 2. Nf3 Nc6 3. Bc4 Bc5 4. b4 Bxb4 5. c3 Ba5 6. d4
If you remember one thing
Count tempi, not pawns. If Black's bishop has moved three times and your centre is built, the pawn was cheap.
Tempo, in plain English
A tempo is a single move of useful time. If your opponent has to move the same piece twice while you develop a new one each move, you are gaining tempi. The Evans Gambit is a machine for gaining tempi.
The deflection
The bishop on c5 controls d4. Remove it — or force it to a square where it no longer supports the centre — and d4 becomes possible. That is the real job of the b-pawn.
The c3 and d4 break
c3 does three things: it hits the bishop, it supports d4, and it gives the queen access to b3 and a4. d4 then opens the centre while Black's kingside is undeveloped.
- —After ...Ba5, the c3-pawn can be pinned against the king — castle before recapturing.
- —After ...Bc5, cxd4 comes with tempo against the bishop.
- —After ...Be7, White has a free hand and can choose d4 or b5.
Why White often delays castling
In some lines White wants Qb3 and Ba3 first because the black king cannot castle anyway. But when Black's pieces are coming out, castling is usually the strongest 'attacking' move — it activates the f1-rook and removes any check-based counterplay.
What Black is threatening
Black's dream is simple: hold the pawn, play ...d6 and ...Nf6, castle, and trade pieces. Every one of White's moves should make one of those four things harder.
Video module: Every Important Defense
10 min, with chapters, captions and a transcript.
Key takeaways
- —Bishop moves → c3 and d4.
- —Pawn moves → look for b5 and Nxe5.
- —Beware the pin on c3 when the bishop sits on a5 — castle first.
- —Declined lines are strategic: take space and aim for a Nd5 outpost.
Transcript
This lesson is your map of Black's replies. There are six you will actually see, plus the declined lines, and each one has a simple rule attached.
After 4...Bxb4 the recipe is always 5.c3. Hit the bishop, prepare d4, and never rush.