Birbal Trilogy Case 1: Finding Vajramuni or simply known as Birbal is a 2019 Indian Kannada-language crime thriller film written and directed by M. G. Srinivas. The film is the first installment of the Birbal Trilogy. It also marked the third character-based trilogy in Kannada cinema, after CID 999 and Sangliyana. It is also the first installment in a cinematic universe followed by Ghost in which M. G. Srinivas reprises his role.

Rukmini Vasanth made her debut as a lead actress. The film introduced an 8D song for the first time in Kannada cinema; it was also the first Kannada film to use the Scribble effect. Its sequels are titled Birbal Trilogy Case 2: Avrn bitt, Ivrn bitt, Ivryaru? and Birbal Trilogy Case 3: Turremane.

The movie was praised for employing the Rashomon Effect in its story narration technique. The movie is based on the 2017 Korean movie New Trial. The Telugu remake of the film Thimmarusu released on 30 July 2021.