Hidefumi Toki (土岐英史) was born in Kobe on 1 February 1950. His own biography says he took up the clarinet and the saxophone in junior high school and turned professional at sixteen, soon after starting high school. He enrolled at the Osaka College of Music, left without graduating, and by his account played there with fellow students including the trumpeter Tiger Okoshi, the trombonist Shigeharu Mukai and the guitarist Kenji Omura, and studied with Shin Sakaguchi. From there he moved to Tokyo and the Shinjuku jazz clubs, where, according to the same biography, he sat in with Sadao Watanabe, the guitarist Yoshiaki Masuo, Takehiro Honda and Kohsuke Mine.

From 1970 he worked in other people's bands. Japanese sources list the groups of the bassist Isao Suzuki, Terumasa Hino, Ryo Kawasaki and Fumio Itabashi, and Japanese Wikipedia says he became lead alto in Toshiyuki Miyama's big band, the New Herd, in 1971. The records bear out the Miyama job: he is credited on alto saxophone and clarinet on the New Herd's Eternity? Epos (Polydor, 1972), on its Superstar with Masahiko Satoh (Philips, 1972), and on alto saxophone on the Columbia album 土の音 〜日本伝説の中の詩情〜 (1973).

In 1974 he formed the Hidefumi Toki Quartet and won the first Shinjuku Jazz Award. The quartet's first record, Toki, was made for Three Blind Mice on 17 May 1975 at AOI Studio in Tokyo, with Kazumi Watanabe on guitar, Nobuyoshi Ino on bass and the American drummer Steve Jackson. Five tracks fill two sides, and the opening "Lullabye For The Girl" runs just over eleven minutes. Nine days later, on 26 May, the same rhythm section joined him and the alto saxophonist Yoshio Otomo at Toshi Center Hall for Lover Man, billed as Alto-Madness: a Charlie Parker tune ("Scrapple From The Apple"), a ballad, and a nineteen-minute blues. He appears the same year on Kazumi Watanabe's Endless Way, on soprano saxophone, alongside Ino and Shigeharu Mukai.

Sky View followed on 12 and 13 January 1976, recorded at Victor Studio for the Frasco label with the pianist Mikio Masuda, the bassist Yoshio Ikeda and Jackson. In 1977 he made Duologue / Heritage for RCA, a direct-to-disc duo with the American drummer Warren Smith on which he plays alto on one side and soprano on the other. His biography says the record earned four and a half stars from Down Beat. The next year he went to New York. On 6 July 1978, at Sound Ideas Studio, he recorded City for Baystate with Tommy Flanagan on piano, Reggie Workman on bass and Joe Chambers on drums, six tracks that include "Speak Low" and "I Love You, Porgy." Back in Tokyo he made You're Dancing for the same label in 1979, with Aki Takase on piano, Ino on bass and cello, Arihide Kurata on drums and Hiroshi Fukumura on trombone.

Most of his working life ran along a second track. From 1977 he was a regular in the studio and touring bands of the singer-songwriter Tatsuro Yamashita, and Discogs credits him on Yamashita albums from It's a Poppin' Time (1978) and Ride on Time (1980) and on to Cozy (1998) and beyond. The same listings carry his saxophone on records by Mariya Takeuchi, Yosui Inoue, Seiko Matsuda, Anzen Chitai, SMAP and B'z. In all, Discogs lists 223 appearance credits for him. His biography also mentions sessions with Ryuichi Sakamoto and an invitation to the Asia Jazz Festival in Macau in 1978.

The jazz work did not stop. With Naoya Matsuoka he played on Joyful Feet (1977) and Day Break (1979), co-produced Pacific Jam (Discomate, released February 1981) with Matsuoka, with the Brazilian singer Flora Purim on three tracks, and in March and April 1981 recorded Brasil in Tokyo as Toki & Samba Friends, with the vocalist Leila Maria, Mukai on trombone and Matsuoka on synthesizer. He also appears on Anli Sugano's Just Groovin' (1980) and on Masayoshi Takanaka's Super Takanaka Live! (1980).

In 1985 he formed ChickenShack with the guitarist June Yamagishi and the keyboardist Toru Tsuzuki, a fusion band that made six studio albums before it stopped in 1991 and returned for a seventh, ChickenShack VII (King Records, 2013). That autumn he arranged and played alto on Captain Tsubasa, an album of music for the football anime, with a studio band under the name Temps. In 1988 he made 1:00 A.M. for Meldac with an American cast: the drummer Leon Ndugu Chancler produced, and Patrice Rushen, David T. Walker, Freddie Washington and Ray Fuller played on it. In 1990, by his biography, he went to Rio de Janeiro as producer for the singer Leila Maria and played the tenth-anniversary concert of the Paris club New Morning with a quartet.

The 1990s brought two quieter records for Fun House: In A Sentimental Mood (1992), a standards date with Hiromasa Suzuki and Soichi Noriki sharing the piano chair and Motohiko Hino on drums, and The Good Life (1994). He appears on Masahiko Satoh's two Randooga albums (1992 and 1993), in a reed section with Kazutoki Umezu and Mine.

From 2008 he recorded steadily for small Tokyo labels: The One (Ragmania, 2008), the sextet record 6/6 Six Sixth (Ragmania, 2011), and Missing What? (Vivid Sound, 2016), on which he shares the alto chair with Akiha Nakashima. When the producer Akiomi Hirano launched the Days of Delight label, Toki's Black Eyes (October 2018) became its first release, catalogue number DOD-001, with the pianist Mayuko Katakura and the trumpeter Hikari Ichihara. A duo record with Katakura, After Dark, followed in 2019, then The Guitar Man with the guitarist Kazuhiko Takeda in 2020. In April 2018 he took up a professorial post at the Osaka College of Music, the school he had left half a century earlier.

Little Boy's Eyes, recorded in Tokyo on 28 and 29 October 2020, came out on 13 May 2021. He passed away of cancer in Tokyo on 26 June 2021, at the age of 71, six weeks later. Live At "RAG", a live set with Takeda, was issued in December 2021. His daughter is the singer Asako Toki, and Discogs credits him as producer on several of her Standards albums, from 2004 to 2014.

Toki's own records are mainstream and post-bop jazz, with a fusion and jazz-funk strand. The 1975 Three Blind Mice dates are long-form quartet playing on blues and ballad material, and Lover Man pairs him with a second alto on a Parker line. From City onward the standards stay close at hand: "Speak Low," "I Love You, Porgy," "My Funny Valentine," "Body And Soul," "Autumn Leaves," "Black Orpheus." He also wrote: "Wyeth," "Blues For Toko & Yoko," "C Minor," "Lady Traveler" and "Little Phoenix" recur across his later records.

Brazil is a second thread. Pacific Jam and Brasil date from 1981, Captain Tsubasa carries Latin percussion, and the singer Leila Maria, who sang on Brasil, was the artist he produced in Rio de Janeiro in 1990. 1:00 A.M. is the clearest of the funk and soul sessions, made with American players under the drummer Leon Ndugu Chancler as producer.

It would overstate things to call him only a jazz musician. Most of the credits attached to his name are pop and kayokyoku sessions, and his longest steady employer was Tatsuro Yamashita. What places him in jazz is the leader catalogue: the Shinjuku Jazz Award, the Three Blind Mice and Baystate dates, the New York session with Flanagan and Workman, the club and festival invitations, and the Osaka College of Music appointment. Japanese Wikipedia lists his genres as jazz, fusion, R&B and pop, and the Discogs genre tags on his own releases are overwhelmingly jazz. He taught as well as played: Japanese Wikipedia names the saxophonist Yota Miyasato, who also tours with Yamashita, as his student, and he taught at the Shobi Music Academy in 1977.