Piano of Sorrow is the 89th episode of the Katekyo Hitman Reborn! anime.
In this episode, Tsuna and Yamamoto learn about Gokudera's past. It is revealed that Hayato is an illegitimate child, born of Bianchi's father, the head of their mafia family, and a famous pianist. Gokudera's mother was only allowed to meet Gokudera three times a year, and died in a car crash when Gokudera was still young that was assumed to be set up by his father. Gokudera doesn't find out that she was his mother until a few years after the crash when he overheard maids gossiping, leading him to run away from home. Meanwhile, at Kokuyo Land, Chrome encountered one of Millefiore's Six Funeral Wreaths, Glo Xinia.