Chess Opening Theory/1. e4/1...d5

Scandinavian Defence
	Position in Forsyth-Edwards Notation (FEN) rnbqkbnr/ppp1pppp/8/3p4/4P3/8/PPPP1PPP/RNBQKBNR
	Moves: 1. e4 d5
	ECO code: B01
	Parent: King's Pawn Opening

1... d5 · Scandinavian Defence

Black takes on White's centre head on. They are determined to disrupt White's centre and immediately open up the board, even if they have to give up their own hopes of big centre and some tempo to do it. The Scandinavian, or Centre Counter Defence, is one of the oldest chess openings, described in a 15th Century Valencian poem.

White could trade the pawn, defend it, or gambit it. 1...d5 is a very forcing response: almost invariably White captures, their plans derailed.

Trade the pawn

2. exd5 is almost always played. It's in White's interest to trade pawns, so they rarely do otherwise.

Usually Black recaptures with 2...Qxd5. This exposes chief drawback of the Scandinavian. Developing one's queen too early makes it a vulnerability, and White can develop 3. Nc3 while gaining tempo on it. For this reason, the modern variation follows up with 2...Nf6, intending to trade off knights first so that 4...Qxd5 can't be met with 5. Nc3.

Defend the pawn

Trying to defend the e pawn comes with trade offs, ranging from small (2. d3?! or 2. Nc3?!) to severe (2...f3?).

2. d3?! lets Black trade pawns then queens, and White loses the right to castle 2... dxe4 3. dxe4 Qxd1 4. Kxd1. Black's achieved equality and the nice open position they wanted but the game is drawish. After 2... dxe4, White can play 3. Nc3!? exd3 4. Bxe3, giving up all their central pawns for some development and transposing into something called the Dunst-Perrenet Gambit.
2. Nc3?! allows 2...d4, kicking White's knight. 3. Nce2 e5 and Black has a strong centre while White is cramped.
2. f3? defends e4 but is very unpleasant for White. If White intends 2... dxe4 3. fxe4, they may avoid the Scandinavian but at the cost of a weakened kingside. However, Black can play 2...e5, leaving the tension, and White's position is awful: they can't play Nf3 because their pawn is there, the king's bishop has no good squares, and Nc3 will be met by d4. White should probably play exd5 anyway, and end up the Scandinavian game they were wanting to avoid, but now they've played f3.
2. e5?! to avoid the pawn trade allows Black to clamp down on d4 with 2...c5, and/or play Bf4 then e6, achieving a superior French defence structure without its passive bishop.

Gambit the pawn

If White really wants to avoid the Scandinavian, then they'd do better to gambit the pawn instead.

2. d4 transposes into the Blackmar-Diemer Gambit, usually seen after 1.d4 d5. It has some chance of leading Black awry if they do not play 1...d5 against 1.d4. If Black prefers to decline the gambit, they can steer the game into the French, Caro-Kann, or Nimzovich defences.
2. Nf3 is the Tennison Gambit. At first it looks like a pre-move mistake, as 2... dxe4 will kick the knight. One plan for White is to win the pawn back only after getting ahead in development thanks to the threat on f7 (3. Ng3 (targets e4 and f7) Nf6?! (defends e4) 4. Bc4 (double attack on f7) e6 5. Nc3 Nc6 6. Ngxe4). Another plan is the internet-famous Intercontinental Ballistic Missile Gambit.

Bad moves

2. c3? allows White to regain the pawn after 2... dxe4 3. Qa4+. White decides that they would rather have their queen bullied about the board to give Black free tempi: 3...Nc6 4. Qxe4 Nf6 5. Qa4 and White is way behind in development.
2. g4? is called the Zilbermints Gambit.

Theory table

For explanation of theory tables, see theory table and for notation, see algebraic notation.

1. e4 d5

	2	3	4
Center Counter with 2... Nf6	exd5 Nf6	d4 Nxd5	Nf3 Bg4	+/=
Center Counter with 2... Qxd5	... Qxd5	Nc3 Qa5	d4 Nf6	+/=
Blackmar-Diemer Gambit	d4?! dxe4	Nc3 Nf6	f3 exf3	=/+
Caro-Kann Defence	... c6	Nc3 dxe4	Nxe4 Bf5	=
French Defence	... e6	Nc3 Bb4	e5 c5	=
Center Counter	Nc3 d4	Nce2 e5	Nf3 Bd6	=
Advance Variation	e5?! c5	c3 Bf5	d4 Nc6	=
2. d3 Variation	d3?! dxe4	dxe4 Qxd1+	Kxd1 Nf6	=
Plano Gambit	c3?! dxc4	Qa4+ Nc6	Qxe4 Nf6	=/+
2. Bd3 Variation	Bd3?! dxe4	Bxe4 Nf6	Bf3 e5!	=/+
Reversed Englund	h3?! dxe4	Nc3 Nf6	Qe2 Bf5	-/+
Tennison Gambit	Nf3?! dxe4	Ng5 e5!	Nxe4 f5!	=/+
Zilbermints Gambit	b4? dxe4	Nc3 Nf6	Bb2 e5!	-/+
Zilbermints Gambit #2	g4? e5!	exd5 Qxd5	Qf3 Qc5	-/+

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Wikipedia has related information at Center Counter Defence

References

Nunn's Chess Openings. 1999. John Nunn (Editor), Graham Burgess, John Emms, Joe Gallagher. ISBN 1-8574-4221-0.

Kasparov, Garry, & Keene, Raymond 1989 Batsford chess openings 2. ISBN 0-8050-3409-9.