Modern Defense

The Modern Defense, also called the Robatsch Defense after Karl Robatsch, answers 1. e4 with a kingside fianchetto and lets White build a full pawn center that Black intends to undermine afterwards. It is a close relative of the Pirc, and the two often transpose. The difference is that the Pirc puts the knight on f6 at once to hit e4, which obliges Black to play ...d6 early. The Modern postpones the knight, keeping the long diagonal open and the choice of setup undecided. The cost is that White, not yet troubled by pressure on e4, gets extra options such as c2-c3 to blunt the g7-bishop. ECO files the Modern under B06 and the Pirc under B07-B09.

2. d4 is the most frequent reply and is generally regarded as the most testing, with 2...Bg7 as the usual response. 3. Nc3 d6 is the Standard Defense. White can then choose the Pseudo-Austrian Attack, 4. f4, with a standard continuation of 4...c6 5. Nf3 Bg4, or the quieter Two Knights Variation, 4. Nf3. Two other plans exploit the delayed knight. Geller's System, 1. e4 g6 2. d4 Bg7 3. Nf3 d6 4. c3, builds a solid center. The Averbakh System, 2. d4 Bg7 3. c4 d6 4. Nc3, gives a King's Indian-type structure in which Black can avoid ...Nf6, for example with the Kotov Variation, 4...Nc6. Black's setups include the ...c6 and ...b5 queenside expansion, the Hippopotamus with both bishops fianchettoed behind pawns on d6 and e6, Tiger's Modern with ...a6 supporting ...b5, and the Pterodactyl with an early ...c5, as in 3. Nc3 c5.

Because Black's position is flexible but slightly passive, White has tried many direct methods. These include the Three Pawns Attack, 3. f4, the Bishop Attack, 3. Bc4, and Bobby Fischer's suggestion 3. h4, which aims to open the h-file with h4-h5. The Monkey's Bum, 2. Bc4 Bg7 3. Qf3, aims at f7 immediately. Its more respected deferred form, 2. d4 Bg7 3. Nc3 c6 4. Bc4 d6 5. Qf3, has been adopted by Judit Polgár, Nunn and Rublevsky, with White usually castling short and pushing f2-f4. On the Black side, the Norwegian or North Sea Defense, 2. d4 Nf6 3. e5 Nh5, sends the knight on a roundabout route. Magnus Carlsen calls this line the "Norwegian Rat" and used it against Michael Adams at the 2010 Olympiad.

The opening had a poor reputation in the nineteenth century, helped by Steinitz's quick win over Augustus Mongredien. It gained respect after the Second World War in the wake of the Pirc. Later exponents include Duncan Suttles, and among British players Colin McNab and Nigel Davies. It ranks among the most common answers to 1. e4 in online play, where results are almost level. Engines give White a slight edge. Besides 2. d4, White often plays 2. Nf3 or 2. Nc3, after which Black can steer into a Sicilian with ...c5.