Finally, the psychological concept called ‘the darkness of the heart’ serves to some extent as the theme of this novel.

Almost a commonplace in the literature of the period, which made much of human emotions, it refers to the dilemma faced by parents who lose a child. Although Buddhist doctrine insists on denial of all worldly attachments, a parent’s love for and the bitter grief attendant on the loss of a child cannot be denied. The term is found in both poetry and prose fiction of the time, for example in the Tosa Diary and Lady Murasaki’s Genji.