Wonderful Fool (おバカさん, Obaka-san) is a novel by the Japanese author Shusaku Endō,[2] originally serialized in the newspaper Asahi Shimbun in 1959.

[4][5] One day Takamori, a young man living with his mother and dominant younger sister Tomoe, receives a letter from Singapore.

After a while they manage to decipher the unusually poor Japanese, and figure out that Gaston Bonaparte, a man who used to be a pen friend of Takamori during his school days, will soon arrive in Japan.

On the expected day, they find the poorly dressed Gaston (a striking contrast to his more famous relative, in the eyes of his Japanese hosts) in the cheapest class, deep down in the ship.

It is clear by the novel's end that Gaston's visit has led the main characters to reassess their lives, Takamori begins to look at the less well off in Tokyo for the first time.