Puzzle of the week #375

Level: 
4-Rook
Chess Diagram: 

[Event "Puzzle #375"][Date "2019.10.20"][Result "0-1"]1. e4 e6 2. d4 d5 3. Nc3 Nf6 4. Bg5 Be7 5. e5 Nfd7 6. Bxe7 Qxe7 7. f4 O-O 8. Nf3 c5 9. Nb5 Nc6 10. c3 a6 11. Nd6 f6 12. Bd3 cxd4 13. cxd4 g5 14. g3 fxe5 15. fxe5 g4 16. Nh4

This was a game played in a tournament where the players could obtain an IM norm. White has infiltrated a Knight into black's defence, while black managed to obtain an open f-file after some risky looking play on the King side. Your tasks:
a) Name the opening
b) How do we call the d6-square where the Knight sits?
c) Was it worth for black do obtain the open f-file? Why?
d) Black to move and win

Total available points for this puzzle is 25. The answers will be published next time together with puzzle #376.

Puzzle #374 solution:
Game Lalic, Susan - Arkell, Guernsey 2001. This week's best answers are by the top scorers:
d) Black's winning idea was to destroy white's center, followed by attacking the castled King
Answers for (a), (b) and (c) throughout the game below

[Event "Puzzle #374"][Date "2019.09.29"][Result "0-1"]1.e4 e6 2.d4 d5 3.e5 c5 4.c3 Nc6 5.Nf3 Bd7 6.Bd3 Qb6 7.dxc5?! Bxc5 8.O-O a5 9.a4 f6! 10.Qe2 fxe5 11.Nxe5 Nxe5 12.Qxe5 Nf6 13.Qe2 O-O 14.Be3 Bxe3 15.fxe3? Ng4 16.Nd2 (16.Qxg4 Rxf1+ 17.Bxf1 Qxb2 18.Ra3 Rf8 19.Qe2 Qxb1 {Black got his piece back and is winning}) Nxe3 17.Rxf8+ Rxf8 18.Kh1 e5! 19.Re1 Ng4 20.h3 Nf2+ 21.Kh2 e4 22.Bb5 Qd6+ 23.Kg1 {Solution} Nxh3+! 24.gxh3 (24.Kh1 Nf2+ 25.Kg1 Ng4 26.Qxg4 {White must give up its Queen to stop the checkmate} Bxg4) 24...Qg3+ 25.Kh1 Rf2! 26.Qxf2 Qxf2 27.Re2 Qf5 28.Bxd7 Qxd7 29.Kg2 Qxa4 30.Nf1 Qc6 31.Ne3 Qf6!

Correct solutions:
Aiden, Matthew - 25 points
Eric, Joey, Harry - 22 points
Walter, Lucas - 18 points
Zach, Zhengyu - 15 points
Glyn - 12 points

Zach - 7 points for puzzle #373

Standings:
Eric - 49 points
Aiden - 48 points
Matthew - 47 points
Harry - 44 points
Joey - 42 points
Zhengyu - 40 points
Walter - 36 points
Lucas, Zach - 22 points
Glyn - 15 points
Lyvia - 11 points

Comment: 

French defence, Classical variation