I've been playing a few puzzles for a couple of days, and I see that often the final move to chessmate is easy to spot, but earlier moves aren't (to me).

In this case, for instance, why should I expect black to defend the king with the rook, rather than, say, eating it with the queen?

```
4rk2/1bq2p1Q/3p1bp1/1p1n2N1/4PB2/2Pp3P/1P1N4/4RK1 w - - 0 2

1. Bxd6 Re7 2. Qxf7

```