Jeremy Good wrote on Tue, Sep 23, 2014 11:04 PM UTC:
Suppose a King is on d1, nightrider on e2 and Harvester on f4. Ordinarily the nightrider should be able to capture the Harvester, but it can't, in this case, because it's pinned and in the process of capturing its pinner, it would illegally leave its king in check. Right?