Sicilian Defense: O'Kelly VariationBETA

Usually arising from a Sicilian move order, this is the starting position of the O'Kelly. Its principal idea is to punish 3. d4 with the sequence 3. ...cxd 4. Nxd Nf6 5. Nc3 e5 followed by Bb4 and central pressure that makes it hard for White to fight for any advantage.

Neither is 3. Nc3 a very good option for White as it leaves Black the option to transpose to a normal Najdorf Sicilian with 3. ...d6 or keep the game in less theoretical waters with 3. ...b5 and quick pressure on the a8-h1 diagonal.

A popular treatment for White is 3. c4 which also gives Black a choice between a transposition to a common opening (the Kan after 3. ...e6) or independent tries with little theory based on a quick Nc6 and e5. In both cases, however, the pawns on c4 and e4 will secure White some space advantage and central pressure.

3. c3 is considered the critical move to exploit the lack of Black development. as White aims to build a pawn center in d4/e4. A variety of moves are possible, most popular are 3. ...d5 (when exd leads to an Alapin structure) or 3. ...e6 4. d4 d5 (when e5 leads to an Advance French. In both systems however Black is a tempo down compared to theory and needs to seek a variation where the move ends up useful.

Generally the O'Kelly is considered most useful as a surprise or in short time controls and on grandmaster level not even that. There is very little theory and games quickly reach unique positions. Very generally, however, it is the Black player for whom the various transpositions are more dangerous and the theoretical verdict has been unfavorable since its inception.