13. Ne5 -- If I was playing black it would be back to Kf8, I would not oblige and to to Kd8. I have been working on this ending with my computer for days. I never even get close in 50 moves. I have read two books on it and STILL, I fail. One GM's book said it took him a week to master it.
But in your solution, the opponent cooperates. Try that with a computer. My guess is that someone who is NOT a titled player I could make 50 moves easily. Even knowing the concepts, rules and ideas, always move toward the wrong color corner. It is almost (not quite) but almost impossible and any decent opponent would not purposely move to the wrong corner if they didn't have to!
You are right in your comments. The opponent cooperates.
Once the opponent's King is in the Bishops colored corner, it is not that hard. But getting there in 50 moves is. And even when the King is in the corner, it takes a few moves. You had better have a few to spare -- and time on your clock.
To a poor miserable reader,
You (the reader), is reading this since it had a "punnish title" and your probably thinking why in the world would this guy not know how to spell "nightmare" correctly?!! Well it is just bad pun... And do mock the insanity of the 2 deadly siblings (knight and bishop)... Well now that you are warmed up, lets get on with something better!!!
Well, I thought I'd post about this since it is quite interesting... Other then the 2 knight combination (which doesn't mate unless you have a nice opponent!), this is an interesting endgames to get the mate out of... It isn't imposible, as I will show you, but this little puzzle is quite interesting.. (disclaimer* it has multiple solutions)..
Mate In 5! Please read the anotations, and realize there is more then one solution but the anotations should explain it...
The idea is to get the opposing king in the corner of the color of your bishop, and have your knight in that magic sweet spot... Here is an example of doing the whole thing... It won't be a puzzle because it is to long but you shold laugh lol =)
This is a 29 move evilness but you should get the idea...