From today's Moomin class, we will take up "Trollkarens Hatt", that I have started to be completely absorbed in solving Moomin stories' secrets. The key to the secrets is "contrast". This work is inlaid with many contrasts which all relate with a silk hat of a wizard who is eager to get the king of ruby. After all, his magic is very contrast. He can change his body into everything, but he cannot change another people into something. He can grant other people's requests, but cannot his own request. Furthermore, his silk hat changes something which is in it into a controversial one. In the last scene, he grant all Moomins' requests one after another, the requests are controversial, i.e. requests for only oneself v.s. for completely other people. After all, people who could resolve such opposition as egoistic or altruistic become happy. It's very philosophical story.