Puzzle of the week #287

Submitted by Eugen on Mon, 11/23/2015 - 19:38

French defence, Tarrasch

Chess Diagram
[Event "Puzzle #287"][Date "2015.11.25"][Result "1/2-1/2"]1. e4 e6 2. d4 d5 3. Nd2 a6 4. Ngf3 c5 5. exd5 exd5 6. Be2 Nf6 7. O-O Be7 8. dxc5 Bxc5 9. Nb3 Ba7 10. Bg5 O-O 11. c3 Re8 12. Qc2 h6 13. Bh4 Nbd7 14. Rad1 Qb6 15. Kh1 Nf8 16. Bxf6 Qxf6 17. Rxd5 Ng6 18. Rd2 Nf4 19. Nfd4 Nxe2 20. Rxe2 Bd7 21. Rfe1 Rxe2 22. Rxe2 a5 23. Qe4 Re8
Replay the game and observe the 2 options white has available for the Queen move: the aggressive 24.Qxb7 and the defensive 24.Qf3 Your tasks:
a) When did the opening end and middlegame begin?
b) Find the best play for black after 24.Qxb7
c) Find the best play for black after 24.Qf3
Total available points for this puzzle is 25. The answers will be published next time together with puzzle #288.

Puzzle #286 solution:
Game Nitura – V E Demian, “Paul Farago” CC Cup ROM 1986-87. The correct answers were:
[Event "Puzzle #286"][Date "2015.11.16"][Result "0-1"]1.e4 e6 2.d4 d5 3.Nc3 Bb4 4.e5 c5 5.a3 Bxc3+ 6.bxc3 Ne7 7.Qg4 Qc7 8.Qxg7 Rg8 9.Qxh7 cxd4 10.Kd1 Nbc6 11.Nf3 dxc3 12.Ng5 {This proved to be a hasty move} Nxe5 {Good move} 13.f4 Rxg5 {Good move} 14.fxg5 N5g6 {Good move} 15.h4 e5 {Good move} 16.h5 Nf8 17.Qg7 Bg4+ {Answer "a": we can consider that middle game began here or at move 19} 18.Ke1 e4 19.Be3 O-O-O {Answer "a" continued from move 17: we can also consider that middle game began here} 20.Qxf7 Ne6 {Good move} 21.Qf2 d4 22.Be2 dxe3 23.Qxe3 Bxe2 24.Qxe2 Rd2 {Good move} 25.Qxe4?? {Blunder allowing mate in 2} Qg3+ 26.Kf1 Qf2#

Correct solutions:
Cody - 15 points
Coco - 13 points
Jalen, Aaron, Bradley - 9 points
Benjamin, Andrew - 7 points
Deryk - 5 points
Ronald, Yakov - 4 points

Deryk - 12 points for puzzle #285

Cody - 133 points
Coco - 112 points
Benjamin - 83 points
Yakov, Jalen - 78 points
Bradley - 77 points
Deryk - 76 points
Terry - 65 points
Aaron - 51 points
Andrew - 48 points
Ronald - 40 points