OK. Black is definitely fighting for a draw. He would like to sacrifice the knight for the g-pawn and leave White with a wrong colored h-pawn. However, he has to get the rooks off the board; I'm pretty sure White wins R+B+RP vs. R, even if it's a bad RP.

I'm not sure, but I think getting the knight to e6 is the key, and 63...Rf1+ might accomplish this. 64.Kxg5 Rg1+ 65.Kmoves Rxg6 should be a drawn rook ending or stalemate. If the king moves away instead, the rook keeps checking until Black can play ...Ne6 safely.

Considering the position on the board, Black's drawing resource is undoubtedly a stalemate trick. The first move has gotta be 63...Rf1+, when 64. Kxg5 makes is easy: 64...Rg1+ 65. Kf6 Kxg6+ 66. Kxg6 produces the stalemate, while any other king move allows 66...Rxg7 with a dead draw.

(a) 64 Kxg5 Rg1+ 65 Kf6 Rxg6+ 66 Kxg6 stalemate. (On any other king move, black takes the g pawn, leading to a drawn position.)

(b) 64 Kg4, and if the white king and the black rook dance around together on the f, g and h files, either the king makes no progress, or eventually black's knight goes to f3 or h3, delivering check and allowing the rook to take white's bishop on g6, followed by the pawn on g7, again leading to a drawn position. If the white king moves west of the f file, the result should be like:

(c) 64 Ke5. And here I think that Ne6 leads either to the capture of white's g pawn and yet another drawn position, or, if the king takes the knight on e6, one of those crazy situations where a rook can harass a king all the way across the board, immune from capture, on pain of stalemate.

Of course, all of this reasoning is bollocks if the various positions I've designated as drawn aren't. But bad as my endgames are, I'm rather confident that an edge pawn that lacks support from the right color bishop for its queening square can typically be stopped, even with each side still having a rook. We'll see.

In fact, after 63...Nh3 64. Rh7, Black can also draw with 64...Rf1+ (64...Nf4 as given by <unionruler> also looks fine), with the possible continuations:

65. Kg4 Rg1+ 66. Kh5?? (66. Kxh3 Rxg6 followed by Rxg7 =) Nf4+ 67. Kh6 Rxg6# ho ho...

65. Ke5 Re1+ 66. Kf6 Rf1+ 67. Bf5 Rxf5+ 68. Kxf5 Kxh7 69. Kf6 Kg8 =.

OK, with white up two pawns, and the white king comparatively safe from checkmate, black must be thinking draw here.

But black must be careful. The combination

63...Kxg7 64 Rxg5 Rxg5

is met with

65 hxg5!

Not 65 Kxg5 as that's a book draw. No, the first thing that comes to mind for me is:

63...Rf1+ 64 Kxg5 Rg1+ 65 Kf6 Rxg6+!

and white can't capture the rook without stalemating black. But anything else, eg:

66 Kf5

allows

66...Rxg7

and another book draw. So, after the initial check, what is white's best move? White has only two other legal moves after 63...Rf1+:

- 64 Kg4
- 64 Ke5

After

64 Kg4

it looks like black can check again on the g-file with

64...Rg1+

and white must move the king to f4 or f5, both of which allow the rook check on f1 again. White doesn't seem to be making progress there. 65 Kf5 truly repeats the position. And

65 Kf4

is met with

65...Kxg7

attacking the bishop. If

66 Rxg5 Rxg5 67 Kxg5

the rook pawn promotes on the wrong color square. And if

65 hxg5 Kxg6

black has the opposition and can draw easily. That only leaves

64 Ke5

which is also met with

64...Nf3+

and white has to allow the capture of the g-pawn by the black king, or after

65 Kf6 Nxh4+

followed by

66...Nxg6

and it's drawn once again.

I think this is all there is to it. Time to check.

=====

i think that both moves, heavily discussed here, 63...Rf1+ and 63...Nh3 lead, with best play, to a draw. the game continuation surely does not, the position after whites 65.Kxe6 is a tablebase win.

from a practical point of view i think 63...Rf1 is much easier to play. in both cases the g7-pawn is lost by force, so the best white gets is an ending with r+b+h-pawn against r+n.

after 63...Nh3 white can force black into a somewhat passive position, say 64.Rh8+ Kxg7 65.Rh7+ Kg8 66.Ra7 leading to

click for larger view

this is with accurate play surely a draw but due to whites acivity and blacks passivity somewhat uncomfortable

on the other hand after for example 63...Rf1+ 64.Ke5 Nf7+ 65.Ke6 Kxg7

click for larger view

blacks life is much easier than in the line above

As a kid I used to love the circus. Clowns, acrobats, jugglers, the flying trapeze. I could even switch off my "don't be cruel to animals" liberalism and enjoy the elephants and tigers. The razzamataz, the sense of danger, of unbridled fun, of romance and slight naughtiness. It's a heady mix of escapism that comes right to your town and for a few brief hours, brings a whiff of the mystery and wonder of the wide world beyond your narrow horizons.

But the one part of the circus that didn't really work for me was tightrope walking. Sure it looks incredibly difficult to do. There's a modicum of danger and a chance of falling. But when all is said and done, tightrope walking is nothing more than slooow walking whilst holding a stick.

Today's puzzle of the day is an example of chess tightrope walking. But to apppreciate it, we need to rewind a move to here:

click for larger view

Black has just played the rather lovely 62...Nxg5. Our tightrope walker is on the wire!

Now if white doesn't have his wits about him, he might play into this fun line: 63. hxg5? Rxg5

click for larger view

We're making slow progress along the wire. Now, of course white cannot capture with 64. Kxg5 and an instant stalemate draw. So he plays 64. Kf6 instead and dreams of 65. Rh8#.

But after 64. Kf6 black keeps on wire-walking with 64...Rxg6+

click for larger view

And now white has to play Kxg6 with the stalemate draw, otherwise black will grab the white rook with Kxh7 and win.

White sees this line, and gives black a chance to go wrong. After 63.... Nxg5 white plays 64. Rh5 bringing us to our puzzle position.

And in the game, black falls off the wire. Wobble, slip, crunch, ouch. Is there a doctor in the house? He plays 64...Ne6, thinking of 65. Kxe6 Rxg6+ and 66...Rxg7 with a draw. Instead, white makes his bishop safe before snaffling the proferred knight with 65. Bh7+ Kxg7 66. Kxe6. And the rest is slow torture.

After 64. Rh5 black was wobbling but could have stayed on the wire with 64...Rf1+ and if 65. Kxg5 Rg1+ 66. Kf5/ Kf6/ Kh6 Rxg6 67. Kxg6 draw.

And here I will do my usual bit and say, for the other variations, see the mighty <dzechiel>, who has performed in front of the crowned heads of Europe...

White threatens 64.hxg5.

The pawn on g7 suggests the possibility of a stalemate. Hence, 63... Rf1+:

A) 64.Kxg5 Rg1+

A.1) 65.Kf5(f6,h6) Rxg6 66.Kxg6 (otherwise 66... Rxg7, draw) and stalemate.

A.2) 65.Kf4 Rxg6 and 66... Rxg7, draw.

B) 64.Kg4 Ne6 with the double threat Nxg7 and Rg1+, Rxg6.

C) 64.Ke5 Nf7+ 65.Ke6 Kxg7

C.1) 66.Bxf7 Rxf7 67.Rg5+ Kf8 looks a draw.

C.2) 66.Bf5 Re1+ 67.Kd7 Kf6 and Black only needs to trade his knight for the pawn.