Puzzle of the week #307

Level: 
5-Queen
Chess Diagram: 

[Event "Puzzle #307"][Date "2017.01.31"][Result "1-0"][SetUp "1"][FEN "2r1r3/p3bk1p/1pnqpppB/3n4/3P2Q1/PB3N2/1P3PPP/3RR1K1 w - - 0 22"]

We have an equal material position, plus both sides have castled and developed. White has an IQP and pieces placed in attacking positions. Black has blocked the IQP with Nd5 and its pieces are well grouped together to provide a strong defence. Your tasks:
a) Identify black's weakness and explain why do you think it is a weakness
b) Figure out a way to attack it and play the best line leading to a win for white

Total available points for this puzzle is 20. The answers will be published next time together with puzzle #308.

Puzzle #306 solution:
Game Yamada – Willemze, 15th Univ. Open (2011). Everyone got answer (a). The other answers were more or less good, so I am going to summarize them here:
a) QGD - Tarrasch defence
b) Black is up a pawn; also it has the pair of Bishops and a battery (Qc7+Bb8) pointing toward white's castle. White controls the d-file and pressures the f7-pawn; however he could have played 19. Rd7 ... and did not do it because losing an exchange (19... Qxd7 20. Nxd7 Bxf4). The fact black's Rooks are not connected can be used as a trick; if white takes the a8-Rook after exchanges, Bb8 can deliver a devastating discovered check on h2 winning material. See line below:

[Event "Puzzle #306"][Date "2017.01.13"][Result "0-1"][SetUp "1"][FEN "rb2r1k1/1bq2ppp/p3p3/1p2N3/1Pp2Q2/P3PB2/5PPP/R2R2K1 b - - 4 19"]19... Bf3 20. Qf3 Qe5 21. Qa8 Qa1 22. Ra1 Bh2 23. Kh2 Ra8

Correct solutions:
Coco, Cody, Bradley - 15 points
Jalen - 14 points
Benjamin, Uros - 11 points
Dheera, Deryk - 7 points

Standings:
Coco, Cody, Bradley - 15 points
Jalen - 14 points
Benjamin, Uros - 11 points
Dheera, Deryk - 7 points

Comment: 

IQP