I think white is busted after 17...bxa6, I won very easily in this correspondence game


when you look at a correspondence database, you'll see that each game after 17...bxa6 that doesn't end with 0-1 was due to (very) weak play by black
interestingly, Vigorito (in his 2010 book) gives 18.Nb4 g3 19.hxg3 fxg3 20.Bxg3 h4 21.Nc6 as "annoying for black"..., while black is probably winning!

a5 And yet it's a difficilt line for a KID player 
1 d4 Nf6 2 c4 g6 3 Nc3 Bg7 4 e4 d6 5 Nf3 O-O 6 Be2 e5 7 O-O Nc6 8 d5 Ne7  9 Ne1 Nd7 10 Be3 f5 11 f3 f4 12 Bf2 g5 13 Nd3 Nf6 14 c5 Ng6 15 a4 h5 16 a5 g4 ( Korchnoi-Xie Jun Amsterdam 2001 ) , and Gallagher , when commenting this game , discusses only 17 c6, but my opponent played   played 17 a6 , that looks stronger
It's not a novelty (I have 3 games in my DB) , but it was never played by GMs
At first time I supposed there was an evident reason not to play it , but it's not the case , so I wonder :
1) Why no GM has ever played yhis move?
2) Why Gallagher dies not discuss it?
Thanks in advance
C Le Page