A Cowardly Heart is the eleventh chapter of Oushitsu Kyoushi Heine manga.
Kai visits Heine's room at night for advice about how to communicate his feelings better. Because of his emotionless face and intense gaze, others often get too scared to talk to him and have the wrong impression of him. His brothers decide to help him out, without much success. Kai is on the verge of giving up, but Heine tells him that instead of trying too much all at once, he should start with simple exchanges like greeting the servants and saying "thank you" to them. Kai decides to try it out and shyly thanks the maid who came to change his sheets. Surprised, she smiles at him, causing an ecstatic Kai to rush to Heine's room to tell him all about it.