Ya'nora kor was a Klingon rite that was exercised by the gin'tak of a Great House. The ya'nora kor allowed the gin'tak to question the fitness of the leader of a family to make decisions, specifically those that had a direct impact on the standing of the House or its future.
In 2370, K'mtar threatened to invoke the right of ya'nora kor to take Alexander away from Worf and send him to the Klingon training academy on Ogat. K'mtar believed Alexander had suffered for his lack of tutelage in combat skills and Klingon ways and believed that Worf's brother Kurn would side with him in seeing this as Alexander's best path. (TNG: "Firstborn")