Do You Know How To Analyse? Part 5

Another quick one I did at lunchtime. I selected it by scanning the solutions for a long variation in one of the last couple of chapters, so I only had a vague recognition of the position. The last few chapters aren't categorised by motif, just things like 'Surprise Moves' - having learnt the motifs in the earlier chapters, part of the excercise is to identify the motif for yourself.

Reinfeld position #811
Black to move

Static analysis: Black has sacrificed a piece for the attack, opening the h-file.

Candidate moves:

A. ... Rh1+
B. ... gxf2+
C. ... Bxf2+
D. ... Nxe4
E. ... Ng4
F. ... Nd4
G. ... Qe7
H. ... Qd7
I. ... d5

F, G, and H with the idea of bringing more pieces to the attack (i.e. in conjunction with 0-0-0) look too slow under the circumstances and ...d5 needs another big idea fast. ... Rh1+ is looking for a Suicide Squad idea but the f2 pawn and time it will take the Queen to get to the h-file put paid to that.

Trying B and C directly lead to positions where Black has exchanged two minors for a Rook and not much promise (though Crafty gives ... gxf2 about -0.6) so my first try was 1. ... Nxe4.

D1. 1. ... Nxe4 2. Bxd8 the basic test of the idea 2. ... Bxf2+ 3. Rxf2 gxf2+ 4. Kf1 Rh1+ 5. Ke2 Rxd1 6. Kxd1 f1/Q+

First I'd tried 2. ... gxf2+ until I realised the pawn promotion idea was better and played the captures the other way around. Black is material ahead after 7. ... Kxd8 but simply

D2. 1. ... Nxe4 2. dxe4 and Black, already two pieces down, has nothing.

Candidate move E has the same idea without exposing the Knight to capture.

E. 1. ... Ng4 2. Be3 (2.Bxd8 is just a better version of D1) 2. ... Nxe3 3. fxe3 (or else Black simply wins the exchange) 3. ... Bxe3+ and we're effectively back in D1 with more material.

Not exactly an exhaustive analysis (in about 20 minutes) but the position was basically cracked that way instead of 'searching for a combo'. Fred's solution:

1. ... Ng4 2. Bxd8 Bxf2+ 3. Rxf2 gxf2+ 4. Kf1 Rh1+ 5. Ke2 Rxd1 6. Nfd2 Nd4+ 7. Kxd1 Ne3+ 8. Kc1 Ne2#.

All very pretty but hardly forced, and I wonder if it's a good thing that I was on the same track as Fred... here's what Crafty says:

1. ... Ng4 2. d4 gxf2+ 3. Rxf2 f6 4. Bh4 Nxd4 5. b4 Nxf3+ 6. Qxf3 Rxh4 7. bxc5 Nxf2 8. Qxf2 9. Bb5+ c6 10. Nc3 Rf4 (-2.5).

All a bit computer-like, but 2. d4 should probably have been the first defense a human should consider too!