TOKU (馬場督之; Baba is the family name) is a singer who also plays the flugelhorn, and he is one of very few jazz musicians in Japan who does both on the same record. He was born on 20 February 1973 in Sanjo, in Niigata Prefecture, and grew up with music through his father's tastes. In junior high school he played cornet in the brass band, then moved on to trumpet and flugelhorn. He attended Niigata Meiai High School and Tokyo International University, where he played rock and pop in cover bands. According to English Wikipedia, a jazz drummer who heard him play Miles Davis's version of "If I Were a Bell" at a campus festival invited him to a jam session, and that was the turn toward jazz. In his third year of university he went to the United States to study English, and the same account places him in Oregon, playing in a band with his roommate, a jazz pianist.

After graduating he sang at the Tokyo jazz club Body & Soul, where the INTER-FM disc jockey Rob Crocker heard him and brought him to Sony Music. The debut album, Everything She Said, came out on 21 January 2000 with Crocker as producer. That August he played Blue Note Tokyo, and in November he gave his first concert abroad, in Seoul. The same year he was already working as a guest: on the Yuji Ohno Trio's Lupin The Third "Jazz" The 2nd (24 May 2000) he plays flugelhorn on two tracks and sings on "Treasures of Time".

The early Sony records are the most conventionally jazz ones. Bewitching (24 January 2001) surrounded him with a largely American cast: vibraphonist Roy Ayers, bassist Buster Williams, drummers Grady Tate and Clarence Penn, pianists Stephen Scott, Charles Blenzig and Aloisio Aguiar, guitarist Adam Rogers and tenor saxophonist Chris Cheek. Chemistry of Love (19 June 2002) was produced and arranged by John Simon, and its bonus track, "You Are So Beautiful", was used in a Hitachi television commercial. Later that year his "Do-Re-Mi" single, used in Honda Odyssey television commercials, widened his audience; its second track, "Mr. Sandman, Bring Me a Dream", has Ron Carter on bass, Grady Tate on drums and Kenny Barron on piano, with Ole Mathisen on tenor saxophone. The album TOKU followed in January 2003, with a Japanese rhythm section of Shinji Akita, Ryo Ogihara, Yasuhiko Sato and Nobuaki Fujii.

Through the middle of the decade he moved easily between jazz and Japanese pop. He sang on m-flo's "Life Is Beautiful" with Double (2004), played flugelhorn for Paris Match and Ann Sally, and in the summer of 2004 formed the group TKY with the bassist Kenji Hino and the guitarist Yosuke Onuma. After Fuji Rock that year they became a quintet with Shinji Akita on keyboards and Hidenobu Otsuki on drums; the album TKY appeared on 23 February 2005, and the group ended by the close of 2005. 30 (2004), A Brand-New Beginning (2006) and Love Again (2008, with a duet with ATSUSHI of EXILE) kept him on Sony while he toured Asia and Europe: Beijing, Shanghai, Paris and Belgium in 2007, the Hong Kong International Jazz Festival in 2008 and the Java Jazz Festival in Jakarta in 2009.

Jazz projects of a different kind came next. In September 2008 he sang "My Ideal" and played flugelhorn on Blue Minor, recorded at Sony Music Studios in Tokyo by Hank Jones's Great Jazz Trio, and he is credited again on the 2011 Memorial of Hank Jones anthology; Keiko Lee is a guest on both records as well. In March 2011, just after the Great East Japan Earthquake, he gave a performance, and he joined Cyndi Lauper's tour of Japan. On 27 April 2011 he released TOKU sings & plays STEVIE WONDER: A Jazz Tribute from Atlanta, then Dream A Dream (26 June 2013), and on 20 May 2015, for the hundredth anniversary of Frank Sinatra's birth, an album made up entirely of Sinatra songs, Dear Mr.Sinatra. Shake (7 June 2017) is a collaboration record with guests from rock, hip-hop and pop, among them Sugizo, Yasei Collective, Zeebra, The Gospellers and Maki Ohguro. Original Songbook (20 February 2019) collected his own songs, with some unreleased material and alternate takes.

TOKU in Paris is the record he made away from Japan. It was recorded from 1 to 7 July 2019 with French musicians, and the Italian pianist Giovanni Mirabassi co-produced it with the singer Sarah Lancman and with TOKU himself, on Mirabassi and Lancman's own label Jazz Eleven. André Ceccarelli and Lukmil Pérez Herrera play drums, Laurent Vernerey and Thomas Bramerie bass, and Lancman sings the lead on the Michel Legrand song "I Will Wait for You". It came out in France first, in early 2020, and he played the Maison de la culture du Japon in Paris on 15 February 2020; the Japanese edition followed on 22 April 2020.

TOKU then left Sony after fourteen albums. On 1 December 2021 he released a five-song Christmas EP, Season's Greetings, on his own, with the Orchestra Ensemble Kanazawa on every track, and in August 2022 the two-disc, 32-track best-of BESTOKU. In October 2021 he began hosting the radio programme City of Jazz on K-MIX in Shizuoka. He has kept playing as a guest: flugelhorn on T-Square's 2023 album Vento De Felicidade, and a vocal on the drummer Clarence Penn's Behind the Voice (2024). A new single, "Time After Time" with the singer Chloe Kibble, appeared on 13 May 2026.

TOKU sings in a crooner's style and plays the flugelhorn as his main instrument, with a tender tone. French reviewers writing about TOKU in Paris described exactly that pairing, a distinctive and gentle flugelhorn sound with a crooner's voice. A performance of Miles Davis's version of "If I Were a Bell" was his own doorway into jazz, and in 2016 Sony Records issued a Miles Davis compilation titled Toku's Selection. His two tribute records show where the voice comes from: the 2011 album of Stevie Wonder songs and the 2015 Sinatra album.

The tilt of his work is toward vocal jazz and standards, with a steady line of originals (he wrote the lyrics and melody of "Still In Love With You" on the Paris album, a song about a trip to Cuba). He also moves in a nearby world that is not strictly jazz: Japanese pop and hip-hop features with m-flo, Double, Ken Hirai, Zeebra, EXILE's ATSUSHI and Maki Ohguro, and advertising work. Those are real and documented, and they brought him a larger audience than most Japanese jazz singers have, but the great majority of his own-name records are jazz albums released as such, and his festival and club work is jazz.