GM Ray Robson was checking this out earlier today. I thought you may enjoy getting a crack at it :)
Thank you Yancey...I think I will put it on a engine tommorrow hopefully and learn the patterns.
I had to hunt in my memory for an ending like this, and the only one I could think of was a Kasparov vs Karpov game from the 1990 Championship match round 16. Kasparov won the ending with a mating attack. However, the situation was different because both players had a pawn faced off on the g-file at g6 and g5, so there wasn't much to learn from it.
I took deeper look at the problem in the Nalimov Tablebase, and here is my impression- white uses mate threats initially to dislodge the arrangement where the bishop protects the knight- once this is accomplished, the two black pieces are vulnerable- for example in the open board, the superior arrangement is for the bishop to protect the night since this puts both on dark squares and the white bishop has no target to aim for, but when black is forced to protect the bishop with the knight, things are less comfortable for black since it allows white to attack the knight with the bishop, and if black has the bishop attacked by the rook, the bishop or knight is lost. Indeed, in the open board, I am quite comfortable hunting the black pieces this way- it makes perfect sense to me. However, my problem is the black king- if black works to keep the pieces nearby the king, such double attacks are harder to work through.
Surpriselover- 1.Kb5 Kd8 2.Bc6 Kc8 3.Ra8?! Kc7! and now what for white? I will give you hint since I have looked this over already in the Nalimov- after 3. ....Kc7, white is in a win 73 moves version whereas with 1.Kc5, it is win in 46.
Nicely done, Alena. I don't know if you saw the earlier comment, but it was Susan's posting of that problem with the two knights vs the king and pawn that reminded me of this puzzle, and it is why I gave it to you.
Kb5 What for black? ...Kd8 Bc6 Kc8, Ra8+ Bb8, Kb6 and obviously this is bad for black. Kb5 Kd8, Bc6 Bd4+, Rb2 Kc7, Rd2 Be5, Kc5 and black appears to be running out of good moves. This is great studying. Point out my mistakes somebody if you want...I have run out of time for now.
Yancey, at last I have found the solution for your puzzle.
I will continue your line after 34. Nc6 Qe6.
I had to remember that two knight could mate if there were pawns.
I can't solve Susan's today puzzle at all. I think one should know how to win rook vs bishop endings and rook vs knights endings brilliantly to win this ending.
I looked this over in the Nalimov Tablebase and conclude it is an inhuman ending. Even looking over the key variations in the first 5 moves didn't really help me understand the plan either.
Whoops. . White posts his rook on b7, not b2
black's bishop/knight combo is formidable ... but I think this might work: post the bishop on c6 and the rook on b2. The rook and bishop have the black king confined to c8 and d8. Then white moves his king around the entire board, down to g2 and h3, h4, g5 and finally f5. From there, the king can drive the black bishop off of e5. The Black bishop at that point is forced to give up defending either the knight or the d6 square.
Alena, did you look at that key position I alerted you to on the big puzzle?
I have looked at this off and on for an hour now, and I still don't have an idea of even a half-assed plan for this. Like Alena, I would be looking for a mate threat, but the truth is I just don't see one here- for example, if white tries 1.Kc6, black just plays 1. ....Kd8- the knight/bishop combo has the white king cut off from d7-d4. I wonder if there is a way to force the black knight to the edge on a dark square and trap him there with the bishop- for example, the knight on f8 with the white bishop on f5. One might combine such a trapping theme with attacks on the bishop/king to win the knight. However, again, I just don't see how to do that.
I think one should use the threat of the mate to win the knight or bishop.