3 Assassins

Grasshopper (Japanese: グラスホッパー, Hepburn: Gurasuhoppā) is a black humour thriller novel by Japanese author Kōtarō Isaka published in 2004 and later translated to English as 3 Assassins. The novel follows a schoolteacher who is drawn into the criminal underworld seeking revenge for the murder of his wife, only to be drawn into protecting a family from a trio of assassins after the target of his revenge is in-turn murdered by someone else. The first novel in Isaka's Hitman trilogy, it was followed by Bullet Train (original Japanese title: Maria Beetle), to which it was marketed as a prequel in English language territories on its translated re-release in 2022, as a tie-in to the Bullet Train film adaptation.

A manga continuation, Maoh: Juvenile Remix, was additionally serialized in Shogakukan's Weekly Shōnen Sunday from June 6, 2007, to June 24, 2009, to which a spin-off series, Waltz, was serialized in Shogakukan's Monthly Shōnen Sunday from October 10, 2009, to February 10, 2012.

The novel was well reviewed, and was adapted as a 2015 Japanese film.