Recorded and filmed as he was dying of cancer, Ryuichi Sakamoto’s “Opus” — the Japanese film composer's posthumous album and documentary of the same name — is clearly meant to be his final farewell. As an album, it is fitting that the 20-song, hour-and-a-half recording of sparse piano played by Sakamoto is a retrospective, taking the listener on a journey through his half-century career. One standout is the first-ever recorded version of the playfully lyrical “Tong Poo” from his early days with techno-pop trio Yellow Magic Orchestra, also known as YMO.

They were pioneers of 1970s electronic music and a Japanese act that landed on the global stage. The album “Opus” is set to be released Friday from Milan Records. It showcases solo piano versions of the film scores that form the pillars of Sakamoto’s legacy, starting with the majestic theme for Bernardo Bertolucci’s “The Last Emperor,” a film set in the final days of imperial China leading into its communist rule.

It won an Academy Award for best original score, making Sakamoto the first Asian to win the honor. The 1987 film, starring John Lone, also won best picture. The score also won a Grammy.

Elsewhere, the track “BB” is Sakamoto’s homage to Bertolucci, a tender love poem for his brilliant collaborator. “Opus” also features the forlornly pensive music Sakamoto did for Bertolucci’s 1990 “The Sheltering Sky,” which juxtaposed emotionally lost American travelers with the ruthless vastn.