Modern Defense


The Modern Defense is a hypermodern chess opening which usually starts with the opening moves:
Black allows White to occupy the with pawns on d4 and e4, then proceeds to attack and undermine this "ideal" center without attempting to occupy it. The Modern Defense is closely related to the Pirc Defense, the primary difference being that in the Modern, Black delays developing the knight to f6. This delay of attacking White's pawn on e4 gives White the option of blunting the g7-bishop with c2–c3. There are numerous transpositional possibilities between the two openings.
The Encyclopaedia of Chess Openings classifies the Modern Defense as code B06, while codes B07 to B09 are assigned to the Pirc. The tenth edition of Modern Chess Openings grouped the Pirc and Robatsch together as the "Pirc-Robatsch Defense". The opening has been most notably used by British grandmasters Nigel Davies and Colin McNab.

2.d4

Main line: 2.d4 Bg7

White's strongest response to the Modern Defense is 2.d4, to which Black typically responds 2...Bg7. The main continuations are:
  • 3. Nc3 d6 4. f4 c6 5. Nf3 Bg4
  • 3. c4 'd6 4. Nc3 Nc6 5. Be3 e5 6. d5 Nce7'
Other possibilities include:
  • 3.Bc4
  • 3.Bd2
  • 3.Bd3
  • 3.f4
  • 3.g3
  • 3.Nf3

    Fischer's 3.h4!?

suggested the move 3.h4 as an unorthodox try against 1...g6 2.d4 Bg7, in his annotation to a game against Pal Benko. The idea is to pry open Black's by h4-h5 followed by hxg6, as...gxh5 would greatly weaken the cover to Black's king.

Averbakh System

The Modern Defense, Averbakh System can be reached by the lines:
  • 1.e4 g6 2.d4 Bg7 3.c4 d6 4.Nc3
  • 1.d4 g6 2.c4 Bg7 3.Nc3 d6 4.e4
Possible moves for Black at this point include 4...Nf6, 4...Nc6, 4...e5, and 4...Nd7. The move 4...Nf6
leads to a position of the King's Indian Defense, where White has options 5.Nf3, 5.f3, 5.Be2, 5.f4, and so on.

Unusual responses

The flexibility and toughness of the Modern Defense have provoked some very aggressive responses by White, including the crudely named Monkey's Bum, a typical sequence being 1.e4 g6 2.Bc4 Bg7 3.Qf3.
Regarding Black responses, other unusual openings can be reached after 1.e4 g6. The Hippopotamus Defense is one such system. Another is the Norwegian Defense which begins 1.e4 g6 2.d4 Nf6 3.e5 Nh5.

Transpositions

Transpositions are possible after 2.c4, for example a Maróczy Bind results after 2...c5 3.Nf3 Bg7 4.d4 cxd4 5.Nxd4 and the Averbakh system is reached after 2...Bg7 3.d4 d6 4.Nc3.
After 2.Nf3, Black can play 2...c5, transposing to the Sicilian Defense, or 2...Bg7. Following 2.Nc3, Black can transpose to a closed Sicilian with 2...c5 or play 2...Bg7.

Kavalek vs. Suttles

In the following game played at the Nice Olympiad in 1974, Canadian GM Duncan Suttles, one of the Modern's leading exponents, defeats Czech-American GM Lubomir Kavalek:

Variations

Monkey's Bum

The Monkey's Bum is a variation of the Modern Defense. Although it may also be loosely defined as any approach against the Modern Defense involving an early Bc4 and Qf3, threatening "Scholar's mate", it is strictly defined by the sequence of moves:
It was discovered and championed by IM Nigel Povah in the 1970s during a wave of popularity of the Modern Defense. In 1972, after Keene and Botterill published their book The Modern Defence, Povah began looking for a response to the opening. He happened across the game Ljubojević–Keene, Palma de Mallorca 1971, which started 1.e4 g6 2.d4 d6 3.Bc4 Bg7 4.f4 Nf6 and eventually ended in a draw. Intrigued by Ljubojević's early Bc4, Povah began investigating a rapid assault on f7 with 3.Qf3. When he showed the first few moves to Ken Coates, a friend at Leeds, Coates declared, "If that works then I'm a monkey's bum!" The name stuck. The Monkey's Bum first appeared in print five years later in the British Chess Magazine. Povah wrote an article on the theory of the Monkey's Bum, in which he stated that although he had never yet lost with the variation, it was still "in its infancy".
In playing the Monkey's Bum, White's idea is to gain active piece play by a sacrifice of the d4-pawn, much like the Smith–Morra Gambit. In practice, however, such compensation proves tenuous in the Monkey's Bum proper, as evidenced by the following game:

Monkey's Bum Deferred

A much more popular and respected approach against the Modern Defense is the Monkey's Bum Deferred. It has been employed by such notable grandmasters as John Nunn, Sergei Rublevsky and Judit Polgár. It is distinct from the Monkey's Bum proper in that the attempt to create the "Scholar's mate" threat with Bc4 and Qf3 only occurs after White has developed their queen's knight. A typical sequence of the Monkey's Bum Deferred is:
Usually White will castle kingside and undertake an attack by means of the pawn thrust f2–f4.
The following spectacular game is probably the most famous success of the Monkey's Bum Deferred and forced it to be considered with respect by the chess world:

Norwegian Defense

The North Sea Variation or Norwegian Defense is a line in the Modern Defense complex that occurs after moves: 1.e4 g6 2.d4 Nf6. A variant in the Norwegian Defense occurs after moves:
Magnus Carlsen calls this variant the "Norwegian Rat".
According to Jim Bickford, one of the characteristics of this defense is the "cork-screw" maneuver the knight makes by traveling to the second rank via f6 and h5. In the introduction to his monograph, Bickford quotes the late Tony Miles as saying "The black knights are better on the second rank – a shame it takes two moves for them to get there." This joke is a reference to the fact that black knights on the second rank would likely occupy the squares d7 or e7; however, in the uncommon openings favored by Miles they tend to wind up on less characteristic squares along that rank, such as f7, g7, c7 and b7.
The Norwegian Defense, Norwegian Gambit was most famously played by Magnus Carlsen against Michael Adams at the 2010 Khanty-Mansiysk Olympiad.