Symmetrical Variation

The Symmetrical Variation, also called the Symmetrical Defense, answers 1. c4 with 1...c5. Black copies White's flank advance, so that Black's pawn watches d4 just as White's watches d5. It is often reached by transposition, with Black delaying ...c5 through orders such as 1. c4 Nf6 2. Nc3 c5, and ECO files it under A30–A39. Neither side has committed a central pawn. The fight is about who can break with the d-pawn first and on what terms, and White's second move largely sets the character of the game.

2. Nf3 prepares an early d4. After 2...Nc6, 2...e6, 2...d6 or 2...g6, White can continue 3. d4 cxd4 4. Nxd4 and reach positions akin to an Open Sicilian. A later e4 produces Maróczy Bind structures from the Accelerated Dragon, Taimanov, Kan or Kalashnikov, while a timely ...d5 points towards the Queen's Gambit Declined. With ...Nf6 and d4 the play becomes the Anti-Benoni, also reached by 1. c4 Nf6 2. d4 c5 3. Nf3, where White avoids a Benoni by not advancing d5. There Black can meet 3...cxd4 4. Nxd4 with 4...e5, pushing the knight back and sidestepping both transpositions. A different route, 1. c4 c5 2. e3 Nf6 3. d4 cxd4 4. exd4 d5, transposes into the Panov–Botvinnik Attack.

2. Nc3, the Normal Variation and the most common reply, makes ...d5 harder to achieve and lets White complete development before breaking the symmetry. A typical scheme is g3, Bg2, e4, Nge2, d3 and O-O, the Botvinnik structure, followed by f4, b4 or d4. If e3 replaces e4, the knight on e2 supports d4. After 2...Nc6 3. g3 g6 4. Bg2 Bg7, the mirrored fianchetto positions arise. The Ultra-Symmetrical and Full Symmetry lines belong here, and the Mecking Variation 5. Nf3 Nf6 6. O-O O-O 7. d4 is White's direct attempt to open the center. Another branch is 2...Nf6 3. Nf3 d5 4. cxd5 Nxd5. White then either confronts the center with 5. d4 or 5. e4 or concedes space with 5. g3. The latter allows 5...Nc6 6. Bg2 Nc7 and ...e5, the Rubinstein System, a Maróczy Bind with colors reversed.

Among Black's setups, the Hedgehog (...b6, ...e6, ...Bb7, ...Be7, then ...a6 and ...d6) leads to long maneuvering games that revolve around pawn breaks. The double fianchetto is resilient, and it can become very drawish when White also places bishops on g2 and b2 and pieces are traded. 2. e4 leads instead to the Sicilian Staunton-Cochrane Variation, the one common second move after which Black outscores White. 2. b4, the Wing Gambit, is a rarity. The engine regards the starting position as roughly balanced, and White scores slightly better in practice.