user9921: Consider the following:
[FEN "r3q1k1/p2p1p1p/b1p2QpB/8/8/2r5/P4PPP/R5K1 b - - 0 1"]

Why is black's next move Qf8? White just follows with Bf8.

user1485: There is no good way to stop Qg7 mate. Black has to give up their queen.

9921: <p>Consider the following:</p>

<pre><code>[FEN "r3q1k1/p2p1p1p/b1p2QpB/8/8/2r5/P4PPP/R5K1 b - - 0 1"]
</code></pre>

<p>Why is black's next move Qf8? White just follows with Bf8.</p>
 1485: <p>There is no good way to stop <code>Qg7</code> mate. Black has to give up their queen.</p>
