Ishihara had scaled back his Nikkatsu output in favour of other studios and his own production company. Nikkatsu viewed new Diamond Line star Tetsuya Watari as a potential successor and they had Masuda remake a number of Ishihara films with him. Masuda loosely remade his own Red Quay into Velvet Hustler (1967) which stars Watari as a "happy-go-lucky" hitman who goes on the run after killing a yakuza boss. The character partially was based on Jean-Paul Belmondo's character in the French New Wave film Breathless (1960). The vigor and humour of the film was something of a departure for both men. The two returned to regular modus operandi in Gangster VIP (1968), which was based on the memoirs of real-life yakuza Goro Fujita. It was the first in what has been called Watari's signature film series and his breakthrough role. Masuda only directed the first film in the series but it provided another blueprint, this time to the studio's New Action subgenre, films which increased the sex and violence quotient while mirroring the tumultuous times of the late 1960s/early 1970s. Nikkatsu's box office returns suffered in the late 1960s and many stars and directors left the studio. Masuda was not happy with the studio system at the time, and in 1968, he quit to become a freelance director—only a few years before Nikkatsu ceased making action films and began producing softcore Roman Porno films in order to remain profitable. Freelance work Remaining a sought after talent, Masuda was approached by the Twentieth Century-Fox Corporation to co-direct the blockbuster American-Japanese co-production Tora! Tora! Tora! (1970) after renowned director Akira Kurosawa left the project. Fox producer Elmo Williams had recommended him based on his Red Handkerchief and reputation as a "creative mind and a disciplined worker". The film depicts the attack on Pearl Harbor from the perspectives of both sides of the conflict. Masuda was responsible for the Japanese segments and asked director Kinji Fukasaku to join him, while American director Richard Fleischer filmed the American segments. The film was poorly received in the United States but did well in Japan. Throughout the next 20 years Masuda helmed a string of major studio productions including Catastrophe 1999: The Prophecies of Nostradamus (aka Last Days of Planet Earth, 1974) and three more big-budget war films for the Toei Company: The Battle of Port Arthur (1980), The Great Japanese Empire (1982) and The Battle