In this game, Paul Keres faces off against A Karu in corr, 1931, where Black shows a strong dominance early on in the game. Upon analyzing this position, the reader may notice how Keres is coordinating both his Bishop and his Knight towards Karu's weak left-side defence. Could Black be planning on using a Bishop-Knight combination? The answer is NO, but the key move in this position is a very subtle one, but a very deadly one as well, 15...cxd4. Here is some of my basic analysis: 15...cxd4 -- An exchange that moves this important Pawn to the d-file which is currently being controlled by Black's Queen. It's compliments are 19...Bf6 which support the progressing Passed Pawn and 20...Re8 which pins the e2 Pawn to White's King. The following diagram is for you to try and come up with the critical follow up moves to this position.
Solution & Explanation: Could you find the moves that Keres did? Well, the solution is 21...d3 22. e4 Bc3+ 23. Bd2 Qd4?! 24. Bxc3 Qxc3+ 25. Rd2 Rxe4+ 25. Qxe4 Qc1+ 27. Rd1 d2#. 21...d3 is immune because if 22. Rxd3 then 22...Bxd3 leaving White in a hopeless position. 23...Qd4?! is a good move because it protects the Bishop on c3 and if 24. bxc4 then 24...Rxe4+. 25...Rxe4+?! --WOW! a move that offers up that Rook in order to remove the defender of the d1 square meaning that if Qc1+ the Rook is forced to d1 freeing up that Pawn on d3 to swoop down and take the King's head with d2#. In all actuality, 25...Rxe4+ is the catalyst that could spark off an array of forced mates including: [26. Be2 Qc1+ 27. Rd1 d2+ 28. Kf1 Qxd1#], [either 26. Qe2/Qe3 => Qc1+ 27. Rd1 d2#], or [26. Kd1 Bxb3+ 27. Rc2 Re1#].