This is the position that I submitted to German grandmaster Karsten Müller (author of [among other books] Fundamental Chess Endings with Frank Lamprecht and Bobby Fischer, The Career and Complete Games of the American World Chess Champion).
White is a pawn up, but it is not clear how he can make headway.
1.Nd2
[I asked the German grandmaster if the basic endgame concept of "opening a second front" might apply here, viz., is 1.h4
a playable alternative? Without giving any lines, he thought it should be considered. The point is that after 1...gxh4
2.Nxh4
Black has to be careful that he doesn't lose the h-pawn. ]
1...Be8
2.a4
Bf7
3.d4?
[According to Müller, this advance violates the important endgame principle "Do not rush..." He suggests 3.Nf3
Bg8
and only now 4.d4
e4
(4...exd4
5.exd4
Nc4
6.Bd3
Na5
7.Ne5
Kc7
8.Bg6
Kd6
9.Bf7
Bh7
10.Bh5
Bg8
11.Bg6
Be6
12.Bf7+-
) 5.Ne5
Kc7
6.Bg6
Be6
7.Bh5
Kd6
8.Bf7
Bc8
9.Bg8
Bb7
10.Bh7
Ke6
11.Bf5+
Ke7
12.Bd7
Kd6
13.Bc6
Bc8
(13...Bxc6
14.bxc6
Nxc6+
15.Nxc6
Kxc6
16.a5+-
; 13...Kc7
14.Bxb7
Kxb7
15.Nf7
Nc4
16.Nxh6
Nxe3
17.h3+-
) 14.Nf7+
Ke6
15.Nxh6+-
]
3...e4
4.h3
Bg8
5.Bc8
After the game was over, several others joined a post-mortem and the piece sacrifice 45.Bxe4 dxe4 46.Nxe4+ Ke6 was suggested. Müller thought that in view of the active position of the black king, White has no real winning chances. In fact both players at this point were in severe time pressure and so...
5...Bf7
6.Bf5
1/2-1/2