An instructional attack by Cordel against Schurig at Leipzig in 1870.
1. Nxh6+ Always look at all checks and captures, but before you do this sacrifice, you have to see the follow up. The key to finding the follow up is that you have to recognize that you have two pieces, each of which are attacking two different squares the king is the only defender of. Of course, there's even more than that as you have to find the follow up to your second move and so on... 1…gxh6 2. Rxf7 Kxf7 3. Qxh7+ Bg7 4. Bxh6 Rg8 5. Rf1+ Black Resigns as mate is coming: Ke6 6. Qf5+ Ke7 7. Qf7#