Puzzle of the week #250

Level: 
2-Knight
Chess Diagram: 

[Event "Puzzle #250"][Date "2014.03.24"][Result "1-0"][SetUp "1"][FEN "r1b1k1nr/ppppbp1p/n7/3NN3/3PP2Q/8/PPP4P/R1B1KB1q w Qkq - 0 1"]

Black is up a full Rook in this position, which is decisive material advantage. Your tasks:
a) Decide who has the advantage overall (center, pieces developed, castling, pieces moved more than once); explain
b) White to move and play the best possible line

Total available points for this puzzle is 20. The answers will be published next week together with puzzle #251.

Puzzle #249 solution:
Bereziuk - Izhnin, USSR 1976.
http://www.chessgames.com/perl/chessgame?gid=1458995
a) Toro's annotations:
1. e4 It is in the centre and it is a common move. Occupies and the centre and is a kingside move. It also lets out the f1-Bishop.
1... c5 Black tries to do the Sicilian. c5 stops White from playing d4. The Black Knight can go to c6 where it is strong behind the c5 pawn.
2. Nf3 It is good because it takes out one of the two pieces between the king and rook so White can castle on the Kingside. It also threatens the d4 and e5. It could also move to g5 or e5 both of which threaten the weak f7-spot. If White moves to g5 it also protects the e4-pawn. But you should only move a piece twice when you have already developed your other pieces.
2... d6 It makes a pawn chain for black and stops white from moving his pawn to e5. Now black can move out his c8-Bishop. But this move blocks the f8-Bishop from moving out.
3. d4 It moves to occupy the centre. If the black pawn takes on d4 then white will recapture with the Knight or Queen. This move also lets out White’s c1-Bishop.
3... cxd4 Black took White’s central pawn but is not developing pieces.
4. Nxd4 White takes the d4-pawn, moving the same piece twice which is not good, but now White occupies the centre.
4... Nf6 Black develops his Knight (Black’s first piece to be developed). Moving out the Knight opens it up for Black to castle after the Bishop is moved. Black’s Knight also threatens the e4 pawn. If Black took the e4 pawn it threatens the f2-weak square.
5. Nc3 It develops a piece and protects the centre. It also could eventually move forward and attack from b5 or d5.
5... a6 It stops the White Bishop from going to b5 which could be bad for Black.
6. Bg5 It almost let’s White castle on the Queenside. It threatens to take the Knight on f6 which would make Black get doubled pawns.
6... e6 It opens the e7-square which would allow black to put his bishop to e7 which would protect the knight on f6 and allows Black to castle.
7. f4 It applies pressure on Black and it threatens to create a bad situation with the pinned f6-Knight. It opens up White’s position but it can castle on the Queenside.
7... b5 It makes a little pawn chain and begins an advance on the Queenside.
8. e5 It attacks the pinned f6-Knight.
8... dxe5 It threatens the d4-Knight with support from the Black queen, but it gets Black into a trap.
9. fxe5 It takes back the pawn and threatens the pinned Knight. If the pinned Knight moves then the Bishop will take Black’s Queen.
9... Qc7 It moves the Queen out of the pin and allows the Knight to move. It also threatens to take the e5-pawn.
10. Qe2 It stops Black from taking the e5-pawn and lets White castle on the Queenside. It also attacks on the e-file.
10... Nfd7 It doesn’t let White take the Knight but it blocks Black’s c8-Bishop.
11. 0-0-0 White castles on the Queenside which protects the King and as the d-pawn has been taken the Rook occupies the d-file.
11... Bb7 It develops the Bishop, threatens the g2-square and occupies the long a8-h1 diagonal. It also opens up the space for Black to castle.
12. Qg4 It protects the g5-Bishop and the d4-Knight and brings pressure to the Black King’s castle. If Black castles White will move his Bishop to h6 and win material.
12... Qxe5 Black took an unprotected centre pawn but put his Queen in the centre which is sometimes dangerous.
13. Bxb5 White takes b5 sacrificing the Bishop in order to move up one of his Knights after taking the second pawn.
13... axb5 Black accepts to take the Bishop and opens up the a-file for the Black rook.
14. Ncxb5 White takes the second pawn and doubles up his Knights. If White can get his Knight safely to c7 then it would be checkmate.
14... h5 Black tries to scare away the Queen and possibly open space for his Rook to come out next.

b) Solution:

[Event "Puzzle #249"][Date "2014.03.18"][Result "1-0"]1.e4 c5 2.Nf3 d6 3.d4 cxd4 4.Nxd4 Nf6 5.Nc3 a6 6.Bg5 e6 7.f4 b5 8.e5 dxe5 9.fxe5 Qc7 10.Qe2 Nfd7 11.O-O-O Bb7 12.Qg4 Qxe5 13.Bxb5 axb5 14.Ncxb5 h5 {Solution} 15.Nc7+ Qxc7 16.Nxe6 Qe5 (16...fxe6 17.Qxe6+ Be7 18.Qxe7#) (16...hxg4 17.Nxc7#) 17.Nc7+ Qxc7 18.Qe2+ Qe5 (18...Ne5 19.Qxe5+ Qxe5 20.Rd8#) 19.Qxe5+ Nxe5 20.Rd8#

Correct solutions:
Coco, Bradley - 18 points
Aaron - 15 points
Mrinal, Jalen, Cody, Toro - 14 points
Brandon, Oliver - 12 points
Benjamin - 4 points
Daniel - 3 points

Standings:
Coco - 183 points
Bradley - 167 points
Benjamin - 131 points
Toro - 122 points
Jalen - 121 points
Anya - 117 points
Oliver - 113 points
Brandon - 110 points
Hyson - 100 points
Ken - 87 points
Cody - 73 points
Mrinal - 60 points
Aaron - 57 points
Eric - 54 points
Daniel - 35 points
Illya - 34 points
Jeffrey - 31 points
Dheera - 16 points

Comment: 

Opening play (2)