As if this is a known and indisputable fact so obvious that it hardly bears discussing aloud, Lan Wangji says, "You are under my protection." It had been easy to see why Claudius feels as he does about Gertrude, and easier still to speak kindly of him to her -- although he is, of course, holding onto the advice he was given for some future game of weiqi in which Claudius might seem to have the upper hand.