What is the second film in the Vengeance Trilogy based on?
The Vengeance Trilogy: The Vengeance Trilogy (Korean: 복수 삼부작 ) is a series of three films, "Sympathy for Mr. Vengeance" (2002), "Oldboy" (2003), and "Lady Vengeance" (2005), directed by South Korean filmmaker Park Chan-wook. Oldboy (2003 film):  It is based on the Japanese manga of the same name written by Nobuaki Minegishi and Garon Tsuchiya.
Japanese manga