Semi-Open Game

A Semi-Open Game (or Semi-Open Opening) is a chess opening in which White plays 1.e4 and Black breaks symmetry immediately by replying with a move other than 1...e5. The Semi-Open Games are also called Single King Pawn, Asymmetrical King Pawn, or Half-Open Games. They are the complement of the Open Games or Double King Pawn Games, which begin 1.e4 e5.

1...c5

Main article: Sicilian Defense

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Sicilian Defense

1...c5, the Sicilian Defense, is by far the most popular of the Semi-Open Games. It is a combative and unbalancing move which often leads to dynamic and sharp positions, and is usually a signal that Black intends to play for a win. It is a heavily analyzed opening rich in tactical opportunities. While 1...e5 remains popular at all levels, 1...c5 overtook it in popularity in tournament games some time in the mid-20th century.

White's most common plan is 2.Nf3 and 3.d4 cxd4 4.Nxd4. This can lead to a variety of named variations classified as Open Sicilians, including the Najdorf Variation, Dragon Variation, and Sveshnikov Variation. Alternative plans include 3.Bb5, chiefly represented by the Rossolimo Variation; 2.c3, the Alapin Variation; and 2.d4 cxd4 3.c3, the Morra Gambit.

Alternatives to 1...c5

a b c d e f g h 8 8 7 7 6 6 5 5 4 4 3 3 2 2 1 1 a b c d e f g h French Defense a b c d e f g h 8 8 7 7 6 6 5 5 4 4 3 3 2 2 1 1 a b c d e f g h Caro–Kann Defense

The French Defense (1...e6) is regarded as a solid option for Black. After 2.d4 d5, Black usually intends to undermine White's center with ...c7-c5. A disadvantage off the French is that Black's light-squared bishop is difficult to develop in the early phase of the game.

The Caro–Kann Defense (1...c6) is similarly motivated, but the light-squared bishop is not restricted after 2.d4 d5, allowing Black to develop it to f5 or g4. A disadvantage compared to the French is that if Black wishes to strike at White's center with a later ...c6-c5, it will come at the cost of a tempo.

The Pirc Defense (1...d6) and the Modern Defense (1...g6) are hypermodern openings in which Black concedes the center to White in the early stages with the intention of attacking it later. These two openings can transpose into each other, the main line of the Pirc being 1.e4 d6 2.d4 Nf6 3.Nc3 g6. Usually the term "Modern Defense" is used to refer to lines in which Black delays ...Ng8-f6 or develops the knight to e7 or h6 instead.

Alekhine's Defense (1...Nf6) and the Scandinavian Defense (1...d5) have made occasional appearances in World Chess Championship games. The Nimzowitsch Defense (1...Nc6) is playable but rare, as is Owen's Defense (1...b6).

The Borg Defense (1...g5?!), favored by British IM Michael Basman, and the St. George Defense (1...a6) are oddities, although Tony Miles once used St. George's Defense to defeat then World Champion Anatoly Karpov. Other replies are almost never seen in serious games and are rarely covered by standard opening references.

List

• 1.e4 a5 Corn Stalk Defense
• 1.e4 a6 St. George Defense
• 1.e4 Na6 Lemming Defense
• 1.e4 b6 Owen's Defense
• 1.e4 c5 Sicilian Defense
• 1.e4 c6 Caro-Kann Defense
• 1.e4 Nc6 Nimzowitch Defense
• 1.e4 d5 Scandinavian Defense
• 1.e4 d6 2.d4 f5 Balogh Defense
• 1.e4 d6 2.d4 Nf6 3.Nc3 c6 Czech Defense
• 1.e4 d6 2.d4 Nf6 3.Nc3 g6 Pirc Defense
• 1.e4 e6 French Defense
• 1.e4 f5 Fred Defense
• 1.e4 f6 Barnes Defense
• 1.e4 Nf6 Alekhine's Defense
• 1.e4 g5 Borg Defense
• 1.e4 g6 Modern Defense
• 1.e4 h5 Goldsmith Defense
• 1.e4 h6 Carr Defense
• 1.e4 Nh6 Adams Defense

See also

• Open Game (1.e4 e5)
• Closed Game (1.d4 d5)
• Semi-Closed Game (1.d4 other)
• Flank opening (1.c4, 1.Nf3, 1.f4, and others)
• Irregular chess opening

References

Bibliography

• De Firmian, Nick (1999). Modern Chess Openings: MCO-14. Random House Puzzles & Games. ISBN 0-8129-3084-3.
• Hooper, David; Whyld, Kenneth (1996) [First pub. 1992]. The Oxford Companion to Chess (2nd ed.). Oxford University Press. ISBN 0-19-280049-3.