In the Sicilian defence, after 1.e4 c5 2.Nf3
in addition to the common replies 2...d6, 2....e6 amd 2...Nc6, Black
has some minor lines among with the Nimzowitsch variation and the
O'Kelly variation are the most interesting.
In the Nimzowitsch variation (2...Nf6)
Black attacks White's pawn centre causing its advance, in order to
show its weakness later. In spite of being a minor and seldom used
line, 2...Nf6 is sound and gives good opportunities
to reach equality. White's has two main option: he can
either challenge Black's second move with 3.e5 or try to switch to Sicilian
main lines with 3.Nc3.
O' Kelly variation (2...a6) is
based upon a smart idea: Black defends the important b5
square in advance, so that White's usual move sequence of the Open
Sicilian is weak, as after 3.d4 cxd4 4.Nxd4 e5! the White Knight
can't jump to b5 (also 5.Nf5 is not possible due to the strong reply
5...d5!). As a consequence Black can take the initiative and has
an easy game ahead. However if White is aware of that he can
create difficulties to his opponent just delaying d4 and playing
instead either an improved version of the Alapin with 3.c3 or an effective Maroczy
Bind with 3.c4.
Other Black's played second moves include 2...g6 that very often leads to an
Accelerated Dragon, 2...b6 (Katalimov variation) that is playable
although too slow, 2...h6, 2...Qc7