A quick look at checks White can give with his bishop turns up Bxd6. Does the move attack anything else? Yes, the knight at e5. The knight is protected by Black’s queen (though also attacked once already by White’s knight on d3), which also protects the d6 pawn. So play with exchanges White can initiate and with the move orders made possible by the threat White already has against e5. A natural possibility to consider is 1. NxN, QxN. This upgrades the target of the fork; it also leaves behind an open line of protection from the White queen to the forking square. Thus Bxd6 now forks king and queen. (Another way to see the idea here is to notice that the Black pawn on d6 is pinned to its king by the bishop at a3, and to look for ways to exploit the pin by taking whatever the pawn protects and pursuing the consequences. Again, trains of thought like this will be the focus of our later study of pins.)