Brain Crusher 1

In a new series of posts I will present a position for the more ambitious player to solve.

As usual, my advice is to set up the position on a board and try to calculate without moving the pieces.  However this time give yourselves 40 minutes on the clock…

Below we have the game Gagunashvili – Zhang Zhong, Jakarta 2011.  Black has just played 19…Nxc3 – How do you proceed as White?