This is what we found on Wikipedia regarding the Pacific Overtures:

Pacific Overtures is a musical with music and lyrics by Stephen Sondheim, and a book by John Weidman, with "additional material by" Hugh Wheeler.

Set in nineteenth-century Japan, it tells the story of the country's westernization starting in 1853, when American ships forcibly opened it to the rest of the world. The story is told from the point of view of the Japanese, and focuses in particular on the lives of two friends who are caught in the change.

Sondheim wrote the score in a quasi-Japanese style of parallel 4ths and no leading-tone. He did not use the pentatonic scale; the 4th degree of the major scale is represented from the opening number through the finale, as Sondheim found just five pitches too limiting. The music contrasts Japanese contemplation ("There Is No Other Way") with Western ingenuousness ("Please Hello") while over the course of the 127 years, Western harmonies, tonality and even lyrics are infused into the score. The score is generally considered to be one of Sondheim's most ambitious and sophisticated efforts.

The original Broadway production of Pacific Overtures in 1976 was staged in Kabuki style, with men playing women's parts and set changes made in full view of the audience by black-clad stagehands. It opened to mixed reviews and closed after six months, despite being nominated for ten Tony Awards.

Given its specific casting and production demands, Pacific Overtures remains one of Stephen Sondheim's least-performed musicals. The show is occasionally staged by opera companies. The cast requires an abundance of male Asian actors who must play male and female parts. As written, women join the ensemble for only half of the last song; all other principal female roles are played by men, as was traditional in Kabuki theatre. In the original production the five female cast members appeared throughout the show in small roles and as stagehands, and more recent productions, including the 2004 Broadway revival, did away with the device of men playing the majority of the women's roles.

The most recent revival in 2017 at Classic Stage Company, helmed by John Doyle and starring George Takei as The Reciter, featured a cast of only 10 people, 8 men and 2 women. This also featured a revised book by John Weidman that had a running time of 90 minutes (as compared to the previous 2 hour 30 minute original run time).