Puzzle of the week #206

Level: 
5-Queen
Chess Diagram: 

[Event "Puzzle #206"][Date "2012.10.28"][Result "1-0"][SetUp "1"][FEN "1q2kb1r/1r1n1ppp/2Qpp3/8/N7/8/1PP2PPP/R1BR2K1 w k - 0 1"]

Sometimes the most innocent looking positions hide nice combinations for quick finishes. This could be one of them if you pay attention to an important element. However before could you pay attention, you have to discover it. Your tasks:
a) Analyze the position and decide what element I am reffering to
b) White to move and win. Please send the best line you can think of for both sides

Total available points for this puzzle is 20. The answers will be published next week together with puzzle #207.

Puzzle #205 solution:
Game Stahlberg – Najdorf, Mar del Plata 1947. James continues to lead with 2 complete answers out of 2 puzzles so far. His solution this time:
a) Material: White is up a pawn
King safety: White's King is safer because there nothing attacking it.
Centre: the centre is semi-open and both sides share it.
I think White has more of a chance because he's up on material, his King is safer and it is his turn to move.
b) Solution:

[Event "Puzzle #205"][Date "2012.10.20"][Result "1-0"][SetUp "1"][FEN "3r4/2q3k1/rp3bpp/2pBp3/2P1Q3/P4RP1/P2R1P1P/6K1 w - - 0 1"]1.Bf7! Kxf7 (1...Rxd2 2.Qxg6+ Kf8 3.Qg8+ Ke7 4.Qe8+ Kd6 5.Qe6#) 2.Rxd8 Qxd8 3.Qb7+ Kg8 4.Qxa6 {White wins}

Correct solutions:
James - 20 points
Danny, Daniel - 19 points
Derrick - 16 points

Ziyao - 10 points for puzzle #204

Standings:
James - 40 points
Derrick - 31 points
Danny, Daniel - 19 points
Richard, Ziyao - 10 points
Raymond - 5 points

Comment: 

Rook's power