So, I take my first glance at this position and I think, "This doesn't look insane. White plays Bxf6 Kxf6 Bxh5 and this should be a walk." At that moment I then considered, "Is it white to move?" Nope, that explains a lot.

OK, first off I think black should play for a draw. White can always sac a bishop for the last black pawn and the two knights will be insufficient to win with the other bishop still on the board.

But, for black to draw, he has to get one of the bishops and both white pawns for his two knights and one pawn. I suppose this can be done, otherwise we wouldn't be here.

I suppose the first thing to look at is

61...Kg5 62 Kxe5

but this leaves only the remaining knight to deal with the two white pawns, as the black king is offside. This doesn't look good for black at all. No, I think that the key move is probably something like...

61...Nc6+

If white tries to move and attack the knight with

62 Kc5

then

62...Ne4+ 63 Kxc6 Nxc3

and black has picked up a pawn and has both white bishops under attack, one of them will fall next move.

I'm not going to pretend that I can actually work this one out to a terminal position, but all manner of things can happen when two knights are dancing their way around the board.

OK, time for me to check and see how this went down.

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It seems obvious that Black has an uphill battle to draw. One thing to know is that it won't be good enough to sacrifice a knight to get White's pawns off; 2B vs. N is normally a win.

First question: will 61...Kxg5 62.Kxe5 be good enough? I don't know, but I distrust B vs. N endings in open positions. Before settling for this, look for something better.

61...Nfg4 or 61...Neg4 leave the same question. 61...Nc6+ at least has a threat to win a piece unless White plays 62.Kc5. Now 62...Kxg5 63.Kxc6 is probably worse than before, with White king more active. But there's a chance to win a pawn instead: 62...Ne4+ 63.Kxc6 Nxc3, keeping both bishops under attack.

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So Black will win a piece, but which one will White save? And will Black be able to hold back the b-pawn with his knight? This is where I start having problems of evaluation.

If I had the puzzle position over-the-board I would probably have gone into the line chosen in the game (61...Nc6+) simply because that would get a White pawn off the board and make drawing that much easier. I wouldn't know for sure if it would work, but it would at least feel best.

Now, here is my analysis :

First of all, let's select the "candidate ideas" :

1)Sacrifice the Ne5 instead of simply letting the White King take it and then take the bishop en prise.

2)Make an active use of the Knight pair

3)Sacrifice the two knights, one for each pawn and then force White to sacrifice a bishop for the remaining f pawn. This has just little chance to ever succeed because the pawn is not far advanced. So we may keep this idea only if there is absolutely nothing.

The position is very tactical, so one idea may lead to another, and auxiliary ideas might be found.

1....Nc6+!! It quickly appears that only the first candidate idea may work

2.Kc5 this is absolutely forced otherwise White loses his bishop.

2....Ne4+!! 2...Nxb4?? fails on 3.Bxf6 so the sacrifice on the knight is brought with threats on the two bishops.

3.Kxc6 Nxc3

I) 4.Bxh5 Kxg5 5.B ad libidum Kf6 = For White to win, he has first to attack the Nc3 so it uses two tempi that the Black king uses to be back in the play. Furthermore, that brings the White king back, and last but no least, the promotion square is a black square, so Mr Black King could be very late that it wouldn't change much.

II) 4.Be3 Nxe2! 5.b5 h4 =

III) 4.b5!? Nxb5 5.Be3 the idea is to save both bishops and then to capture the h5-pawn. Interesting it may be but 5....Ke4! and 6....Nd4+ draws it =

IV) 4.Bd2 Nxe2 is no probem = Why did I just calculate that ?! Well, sleeping unsifficiently might be a plausible explanation ... :)

So can black force a draw? Only by taking both white pawns and a bishop I think. So what happens if we attack the pawns immediately?

61 .. Nc6+
62 Kc5 .. or black goes up a piece
62 .. Ne4+!

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If 63 Kxc6 Nxc3 and one or other of the bishops goes next move.

Any other move 63 .. Nxc3 or 63 .. Kxg5 as appropriate.

Black wins the pawn race

60 b4 h5 61 b5 h4 62 b6 h3 61 b7 h2

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Initial impression: Black has excellent losing chances and no significant tactic, so it is Black to play and draw. The key decision is: exchange N for B or keep the Ns centralised?

A Exchange off N for B: Try 61..Kxg5 62 Kxe5 Ng4+ Now 63 Bxg4? hxg4 64 b5 g3 65 b6 g2 66 b7 g1=Q 67 b8=Q Qh2+ 0-1 so clearly White won't fall for this. Instead 63 Ke6 h4 64 Bxg4 Kxg4 draws easily, but White can try for more with 64 Bf3 and will probably get it.

B Keep both Ns centralised: Try 61...Nd5 62 Bh4 Now the immediate 62...Ng6? allows Bd3 exchanging N for B on White's terms, but 62...Nc6+ forces 63 Kb3 (to escape a repetition) Ng6 and Black's Pawn can advance. Will this be enough to draw?

C Exchange off N for B starting Nc6+: 62 Kc5 Ne4+ 63 Kxc6 Nxg4 (or perhaps Kxg4): both these lines seem to have similar drawbacks to line A.

I think lines A or C are clear White wins, so I choose Nd5 as giving Black most drawing chances. Time to see how the game went:
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Missed it! In line C 63 Nxc3!! and Black has two Bishops en prise. Congratulations to the regulars. Well at least I avoided line A.

<Phony Benoni: Endgames can make very difficult puzzles [snip] One thing to know is that it won't be good enough to sacrifice a knight to get White's pawns off; 2B vs. N is normally a win.> Well worth knowing, thanks!

Setting up the puzzle colours reversed as White to play and draw:

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J M Lopez-Martinez vs M Narciso-Dublan, 2008 61...? colours reversed Crafty End Game Trainer check: http://www.chessvideos.tv/endgame-t...

Working on the principle that the white K cannot both block BK from b8 and dislodge Nc3 ...

61 .. Nc6+ 62 Kc5 Ne4+ 63 Kxc6 Nxc3 64 Bxh5 Kxg5 65 Be8 Kf6 66 Kd6 Ne4+ 67 Kd5 Ke7 68 Bc6 Nc3+ 69 Ke5 Kd8 70 Kd6 Kc8 71 Bg2 Kb8 72 Bc6 Kc8 73 Bg2 Kb8 74 Bc6 Kc8 1/2-1/2

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There's only one correct way for white to win for white's first four moves, with best play by both sides.

Click on the the link below and paste the FEN string from the puzzle position into the Java applet to find the solution.

Analysis by Rybka 4 x64:

depth: 27 : 65 min :

1. (0.54): 61...Nc6+ 62.Kc5 Ne4+[] 63.Kxc6 Nxc3[] 64.Bxh5 Kxg5[] 65.Be8 Kf5 66.Kc5 Ke6 67.Kd4 Ne2+ 68.Kc4 Kd6 69.b5 Nf4 70.b6 Nd5 71.b7 Kc7 72.Kxd5 Kxb7 73.Bc6+ Ka6 74.Kc5 Ka5 75.Bd7 Ka6 76.Bb5+ Ka5

2. (4.03): 61...Ne4 62.Bh4[] Nc6+ 63.Kd3[] Ne5+ 64.Kc2[] Ng6 65.Bd8[] h4 66.Bf1[] Kg4 67.b5[] Nc5 68.b6[] Nf4 69.Bc7 Nfe6 70.Kd2 Kf3 71.c4 Ne4+ 72.Kd3 N4c5+ 73.Kc3[] Kg4 74.Kd2[] h3 75.Ke3 Nd7 76.Kf2 Nec5

White threatens 62.Bxf6 and 63.Bxh5, and to push the passed pawns.

Black can try to attack the bishops and the pawns with the knights and king. Therefore, 61... Nc6+ 62.Nc5 (otherwise 62... Kxg5) Ne4+ 63.Kxc6 Nxc3:

A) 64.Bxh5 Kxg5 and Black can probably achieve draw.

B) 64.Bd2 Nxe2 and Black is better than in line A.1.

Black to play (61...?) "Insane"

I'm doing this a little late (gone all day), but wanted to see if I could get this before the all-to-easy Monday comes around!

61...Nc6+! 62. Kc5

Forced, as otherwise Black wins a piece for free with 62...Kxg5.