Here's one that came up today that I thought was interesting. I'm kind of cheating because I've examined it quite a bit on my own now, but I'm still not entirely sure I know what to do with it.
White to move, 15th move in a French Defense game.
A little spoiler space before I get into my thoughts on the position, which I don't want to have the entire post be in spoiler text.
...
...
...
...
...
Okay, white essentially has two options. The first is to continue with his kingside expansion thematic to his triple-castle and try to pawn storm up the board.
15. f5 is the best option to do that, but it takes some calculation and vision to see that. 15. f5 exf5 16. Nxd4 will leave white with some nice tactical opportunities that should lead to a winning edge (computer considers the best line to be 16. Nxd4 Qh6+ 17. Kb1 b6 18. b4 Na4 19. Ne7+ Kh8 20. Qxd7 Nc3+ and white will get two minors for his rook, plus have a better overall position).
After 15. f5 Rac8 16. f6, white will get the mating attack chances he wants, but there's still counterplay for black:
The other option is 15. b4, which forces the line 15. b4 Na4 16. Nxa4 Qxd4 17. Rxd4 Bxa4, which leads to this position:
I'd be interested in thoughts on this endgame. The computer thinks white stands better here. He's got a king with better access to the center, and his bishop is completely free while black's is hampered by his pawns. But I just don't know, because black's rooks seem to be able to get active more quickly.