Very nice study

To start this snowy December, here is a "not so simple not so hard" study of Herbstmann.

[Event "Niv 2"] [Site "?"] [Date "????.??.??"] [Round "?"] [White "Etude Herbstmann"] [Black "?"] [Result "*"] [SetUp "1"] [FEN "8/4B1pp/8/pp1PppP1/b3p3/P7/P3KP1P/2k5 w - - 0 1"] [PlyCount "11"] 1. g6 $3 (1. Bb4 Bd1+ 2. Ke1 Bh5 3. d6 Be8) (1. d6 b4) 1... hxg6 2. Bb4 $1 Bd1+ (2... axb4 3. d6 $18) 3. Ke1 Bg4 4. Bd2+ Kc2 5. Bf4 $1 exf4 6. d6 $18 *

White to play and win.

Hint : the first idea doesn't work immediately. The second idea does but you will have to find a third idea for that!