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Chess Opening Theory/1. e4/1...c5/2. Nf3/2...e6/3. d4/3...cxd4/4. Nxd4/4...Nc6/5. Nb5/5...d6/6. c4/6...Nf6/7. N1c3/7...a6/8. Na3
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Szén variation B45 Szén variation
8. Na3
White saves their knight with 8. Na3.
The position is looking cramped for Black. Those pawns on c4 and e4 prevent them from playing d5 and gaining more space. Meanwhile, Black's pawns on d6 and e6 prevent Black from developing their bishops very actively.
They have three typical continuations.
Black still has their bishops to develop, so option one is to develop their light-square bishop, in which case first Black must play 8...b6 to make room to fianchetto it.
Option two is to develop their dark-square bishop. Fianchettoing it is inconceivable of course because of how weak f6 will become. Since White induced them to play 5...d6, there is only one place left for it, so Black may as well play 8...Be7 and get it over with, then at least they can castle.
Option three is to discard both these options as too timid, throw caution at the wind, and kick open the Maroczy bind with 8...d5 anyway. This is an especially good continuation if it is 1985 and you are Garry Kasparov, after whom the audacious play, the Garry gambit, is named.
Theory table
References
See also
Sicilian Defence
The Sicilian Taimanov Pavlidis Antonios Quality Chess UK 2019 978 1 78483-058 8 Glasgow