Yesterday I offered this position, from a 1944 battle between future world champion Mikhail Botvinnik and one Abram Khavin:
It's Black to move, and the question is whether he can safely grab on d4. When you think you've got it figured out, click below.
The answer is yes - as long as you take it the right way.
(1) 23...Nxd4? is wrong. Botvinnik gives 24.Qxd5 in his notes, rightly claiming an initiative for White, but interpolating 24.Rxe8+ Qxe8 and only then 25.Qxd5 gives White a winning advantage, thanks to Black's weak back rank. (For example, if 25...Ne6 26.Nxe6 Bxe6 27.Qg5 wins, thanks to the threats of 28.Qxh4 and 28.Rd8.)
(2) 23...Rxd4 is right, but only because of a spectacular shot. After 24.Nxf5 Bxf5 25.Qxf5 Black appears lost - obviously lost at that. But then have a look at the position after 25...Qe7!!
After this fantastic move, White has nothing better than a luft move like 26.g3, and then everything equalizes out: 26...Rxd1 27.Rxd1 Qxc5 28.Qxd5 with a drawn position.
In the game, Black missed this idea (as did Botvinnik - it was found by translator Ken Neat [or his computer]), and played 23...Rxe1+, accepting an inferior but tenable position. For the rest of the game, with further comments, click
here for the replayable board.