[Comment "auto-generated from "]
[Event "Analysis"]
[Site "Benoni Pirc"]
[Date "2015.01.01"]
[Round ""]
[White "9.f5"]
[Black "8...Rb8 variation"]
[Result "*"]
[EventDate "2015.01.01"]

1.e4 d6 2.d4 Nf6 3.Nc3 g6 4.f4 Bg7 5.Nf3 O-O 6.Bd3 Na6 7.O-O c5 8.d5 Rb8 9.f5 gxf5 10.exf5 {This is best.} 10...Nc7 {Also best, although 10...b5 looks more or less playable.} 11.Ng5 
    ( 11.Qe1 b5 12.Qh4 
        ( 12.Qg3 c4 13.Nd4 Kh8 14.Nc6 Qe8 15.Be2 Rb6 {Unclear.} )
        ( 12.Ng5 c4 13.Be2 Bd7 14.Qh4 Qc8 {Black is slightly better. Black will bring in extra defence via f5.} )
    12...c4 13.Be2 Bb7!? 14.a4 b4 15.Ne4 Nxe4 16.Qxe4 Bxd5 {Unclear. Black does not look worse, even though white may regain his pawn.} )
11...b5 12.Nge4 Nxe4 {Best even though it looks strange to exchange this well entrenched knight.} 13.Nxe4 
    ( 13.Bxe4 Ne8 14.Bd3 c4 15.Be2 Nf6 {Looks OK for black.} )
13...c4 14.f6! {This is the point behind white's play. He has gained a chance to secure a structural advantage.} 14...exf6 15.Be2 f5 {I don't think alternatives here are better. Black should use this pawn while it is still alive.} 16.Ng3 Re8 17.a4 {White probably needs to try this. If he can weaken black's structure enough the position may in the long run become favorable.} 
    ( 17.Nxf5 Bxf5 18.Rxf5 Qe7 19.Bh5 Qe1+ {Should be OK for black.} )
17...a6 {I think this is best although there are a few interesting alternatives. White's play has almost been forced untill now but here he has a few alternatives.} 18.Nxf5 {Simplest and not such a bad try for an edge.} 
    ( 18.c3!? {More complicated.} 18...Be5 19.axb5 
        ( 19.Nxf5 Bxf5 20.Rxf5 Qh4 21.g3 Qe4 22.Rf2 Qxd5 23.Bd2 f6 {With compensation but probably not more.} )
    19...Qh4 20.b6 f4 {With some counter chances. One line now is:} 21.Bxf4 Bxf4 22.bxc7 Rxb2 23.Bh5 Bxg3 24.Bxf7+ Kg7 25.hxg3 Qe4 26.Rf3 Qe2 27.Qf1 Qxf1+ 28.Kxf1 Ree2! {Equal. With a perpetual check mechanism.} )
    ( 18.axb5 axb5 19.Nxf5 
        ( 19.c3 Re5 20.Bf3 Na6 {Unclear. Black may sacrifice an exchange on e5 to plant a knight on d3.} )
    19...Bxf5 20.Rxf5 Re5 21.Rxe5 Bxe5 22.g3 Ra8 23.Rxa8 Qxa8 24.Bf3 Qa1 25.b3 cxb3 26.cxb3 Nxd5 27.Bxd5 Bb2 {Equal.} )
18...Bxf5 19.Rxf5 Qe7 20.Bh5 
    ( 20.Bf1 Qe4 21.Qh5 Qxc2 22.Bf4 Qxb2 23.Qxf7+ Kh8 24.Rd1 bxa4 25.Qxc7 Rbc8 26.Qd7 a3 27.Rf7 Rcd8 {Unclear. Is probably OK for black.} )
20...Qe1+ 21.Rf1 
    ( 21.Qxe1 Rxe1+ 22.Kf2 Rxc1 23.Rxc1 Bxb2 {Unclear. Looks like a nice exchange sacrifice. Note that the a-pawn will become dangerous.} )
21...Qxd1 22.Rxd1 a5 {Perhaps white can claim a tiny edge. Black looks quite OK though.} *