Kei Marimura (真梨邑ケイ, sometimes written 真理邑ケイ) is a Japanese jazz vocalist, actress and author, born on August 29, 1957, in Chiyoda, in central Tokyo. Her career has always run on two tracks that she has never tried to separate. As a singer she is a standards vocalist who made her major-label debut in 1982 and has recorded for Discomate and Teichiku's Continental label; as a public figure she has worked since 1976 as a television and film actress (her early credits are under her birth name, Kawaguchi Kyoko, 川口今日子), a photo-book and image-video subject, a film director and a novelist. Her jazz records are the subject of this profile, and the acting and entertainment side is stated here plainly so that the two are not confused.

She grew up in Chiyoda, attended Shoei Girls' school, and after graduating trained as an actress at the Toho Gendai-geki research institute. Her official profile says she was signed in 1982 by the Ozawa music office, whose president came to her himself, and that the same year Discomate released her first album, Elegance, which she describes as her debut as a jazz vocalist on the major-label side. The record was arranged by Norio Maeda, produced by Jiro Inagaki, and backed by Maeda's Wind-Breakers, the quartet of the clarinettist Eiji Kitamura and the Yasuo Arakawa Trio. Discogs credits Masahiko Ozu among the drummers, with Tadayuki Harada on baritone saxophone and Konosuke Saijo on tenor. Her official profile names Kitamura as the senior player who first heard her as a jazz singer and had her sing with his quintet before she had a record contract, and says she also sat in with George Kawaguchi's Big Four before her debut. Mood Indigo followed in November 1982.

Television amplified the debut. In the 1982 to 1983 season she co-hosted the TBS music programme Yoru wa Kibun de with Kitamura, and Japanese Wikipedia lists a TBS radio jazz programme of hers that ran from 1982 to 1987. Her third album, The Man I Love (Discomate, 1983), is the record she is best known for as a jazz singer. Discogs credits Nelson Riddle as an arranger alongside Maeda, with Maeda's Wind-Breakers and Toshio Mori and Blue Coats as the bands; her official profile and Japanese Wikipedia both say the trumpeter Harry James guested, and Discogs credits Harry James on trumpet on Favourite Standard, the 1984 CD compilation that draws on these albums. The album reached the top ten of the Oricon album chart and earned a gold disc, and Japanese Wikipedia says it won a hit award and a work award; her own profile gives its sales as over 40,000 copies, which she calls unusual for a jazz vocal record. P.S. I Love You (1983) and the concert album Beautiful Dreamer Live (1984), which has a companion laserdisc recorded live on July 11, 1983, followed; Inagaki is credited as producer on five of her Discomate releases between 1982 and 1984.

In 1985 she moved to Teichiku Records and its Continental label. That year she sang a duet single with the film star and singer Yujiro Ishihara, "Sayonara wa Hirusagari," a kayokyoku release that is her best-known work outside jazz and the release her Spotify artist page features. Tiempo de Amor (November 1985), arranged by Makoto Matsushita, leans toward Latin pop and what Discogs files under City Pop; the 1986 singles "Shiseikatsu" with "Final Flight" and "Starlight Lover" with "It's My Night" lean the same way. Her return to jazz material came with La Califusa (November 1986), a bossa nova and Brazilian set recorded at Monterey in Los Angeles and Eastside Studio in New York, with the guitarist John Pisano, the harmonica player Toots Thielemans, the percussionist Paulinho Da Costa, the saxophonist Justo Almario and the drummer Claudio Slon credited on it. The Continental (1987) is a collection of songs from the 1930s musicals and films, played by a large studio band with Makoto Yano conducting and, in the trumpet section, Jun Miyake.

The 1990s records are the most mixed. She produced Nouveau (1991), arranged by Kazumi Watanabe and Kiyoshi Morita, and Mucho Mucho (1992) is a set of Latin standards; Discogs files both under pop. Her official profile says she has released 35 albums in all, a larger number than Discogs shows under her name. A two-disc Brilliant Best from Teichiku followed in November 2010, collecting the 1980s jazz and bossa nova recordings.

Away from music she wrote and directed the film Mermaid (2001), published the novel Intimacy (Tokuma Shoten, 2011) and appeared in many films and television dramas, including Yasha (1985) and the Toei police film Mottomo Abunai Deka (1989); she has more than a dozen photo books to her name and, in September 2009, released an adult-oriented image DVD, Jyoji, which the ZAKZAK entertainment site covered at the time as a release by the jazz singer. In March 2022 she marked forty years since her debut, and her official blog shows her still performing jazz concerts and appearing in films in 2026, including a new film, Akai Jitensha, whose completion screening is set for November 11, 2026. She turned 69 in August 2026.

Marimura's jazz is a standards singer's: the American songbook of the 1930s through the 1950s, sung straight and arranged for big band or a small swing group. The tracklists show it plainly: "The Very Thought of You," "Bewitched," "On a Slow Boat to China," "Autumn Leaves," "Cheek to Cheek," "Take the A Train," "You'd Be So Nice to Come Home To." Her own profile lists Chet Baker, Stan Getz, Nat King Cole, Frank Sinatra, Tony Bennett, Doris Day, Billie Holiday, Peggy Lee and Anita O'Day among her favourites, and says the 1930s to 1950s American standard repertoire is what she sings. It also reports that the original liner notes for Elegance, by the critics Hisamitsu Noguchi, Shoichi Yui and Kei Aoki, welcomed her as a throwback to a 1930s torch singer with some of the nostalgic charm of Doris Day.

The arrangements are the other half of the sound. On the 1982 to 1984 records they come from Norio Maeda and, on The Man I Love, Nelson Riddle, which puts her in front of a big-band or swing orchestra rather than a trio, and Discogs tags The Man I Love as Big Band and several of the albums as Vocal. From 1985 her records branch out: the Latin pop of Tiempo de Amor, the bossa nova of La Califusa, the jazz-funk and City Pop of the 1986 singles, the film-musical standards of The Continental and the Latin repertoire of Mucho Mucho.

How to place her is a fair question. Discogs labels the 1982 to 1984 albums, La Califusa, The Continental and the 2010 best-of as jazz, and labels Nouveau and Mucho Mucho as pop; she is also a known actress, a kayokyoku duet partner of Yujiro Ishihara, and a long-running photo-book and image-video subject. Her own web profile and blog describe her as a jazz vocalist first, and her recorded legacy is overwhelmingly standards and bossa nova, so she is treated here as a jazz singer who also has a large public career in entertainment.