was born in Hiroshima in 1955. In 1976–86 he studied in Germany with Isang Yun at the Hochschule der Künste in Berlin and Klaus Huber at the Staatliche Hochschule für Musik in Freiburg. In 1980, he participated for the first time in the Summer Courses for New Music in Darmstadt. Since then, he has been working as a composer mainly in Europe and Japan, gaining a reputation as one of the leading Japanese composers and receiving commissions from leading orchestras, music festivals and opera theatres in Europe and America.

His most renowned works include notably the opera HANJO commissioned by the Festival d’Aix-en-Provence in 2004 (staged by Anne Teresa De Keersmaeker), Circulating Ocean for orchestra, commissioned by the Salzburg Festival in 2005 (premiered by the Vienna Philharmonic), Woven Dreams, awarded at the Roche commissions in 2008 (for Lucerne Festival and Carnegie Hall, premiered by Cleveland Orchestra at the 2010 Lucerne Festival), his third opera Matsukaze commissioned by La Monnaie in 2011 (staged by Sasha Waltz), the Horn Concerto Moment of Blossoming, commissioned by the Berlin Philharmonic, Barbican Centre London and Concertgebouw Amsterdam (premiered by the Berlin Philharmonic in 2011) and many others were premiered by leading conductors including Kazushi Ono, Jun Märkl, Kent Nagano, Sir Simon Rattle, Robin Ticciati, and Franz Welser-Möst.

In 2001, Hosokawa became a member of Akademie der Künste in Berlin. He was composerin-residence with Tokyo Symphony Orchestra (1998–2007), Deutsches Symphonie Orchester in Berlin (2006–07), and WDR Radio Choir in Cologne (2006–8). In 2006/7 and 2008/9 he was a fellow at the Wissenschaftskolleg in Berlin. In 2012, he was elected member of Bavarian Academy of Fine Arts in Munich.

At the 2013 Salzburg Festival, many of his works were performed, including two premieres: Klage for soprano and orchestra (his second commission by the festival) and Ancient Voices – In memory of Wolfgang Schulz for wind quintet (commissioned by Ensemble Wien–Berlin).

Currently, he serves as Music Director for the Takefu International Music Festival, and is a guest professor at the Tokyo College of Music and Elisabeth University of Music.

Major works (since 2000): Ceremonial Dance for string orchestra (2000), Concerto for Percussion and Orchestra Wanderer (2000), Ancient Dance for violin and piano (2000), Voyage IV Extasis for accordion and ensemble (2000), Cloudscape for organ (2000), Metamorphosis for clarinet, string orchestra and percussion (2000), Voiceless Voice in Hiroshima for soloists, narrators, chorus, tape and orchestra; recomposition of Hiroshima Requiem (1989–2001), Voyage V for flute and chamber orchestra (2001), A Song from Far Away – In Nomine for six players (2001), Re-turning In Memory of Kunio Tsuji, concerto for harp and orchestra (2001), Herbst-Lied for clarinet and string quartet (2001), In die Tiefe der Zeit for clarinet and accordion (2001; version for violoncello and accordion, 2003), Slow Dance for six players (1996– 2002), Sen II for cello (1986–2002), Somon-ka for voice, koto, cello and chamber orchestra (2001–2), Voice from the Ocean for orchestra (2001–2), Re-turning II for harp (2001–2), Reminiscence for marimba (2002), Meeres Licht for soprano, alto, choir and orchestra (2002), Wie ein Atmen im Lichte for shō (2002), Voyage VI for viola and strings (2002), Silent Sea for piano, string orchestra with percussion (2002), Im Frühlingsgarten for nine instruments (2002), Garden at First Light for gagaku ensemble (2003), Floral Fairy for string quartet (2003), Singing Garden for six players (2003), Hanjo, opera in one act (2003−4), Mein Herzensgrund, unendlich tief for mixed choir and marimba (2004), Drawing for eight players (2004), Gesine for harp (2004), Voyage VII for trumpet and strings with percussion (2005), Circulating Ocean for orchestra (2005), Herbst Wanderer for saxophone, piano, percussion and string orchestra (2005), Three Love Songs for voice and alto saxophone (2005), Etude for Bass Clarinet (2005), Wind from the Ocean for orchestra (2003–6), Voyage VIII for tuba and ensemble (2006), Lotus Under the Moonlight – Hommage à Mozart for piano and orchestra (2006), Die Lotosblume – Hommage à Robert Schumann for mixed chorus and percussion (2006), Skyscape for orchestra (2006−7), Danses imaginaires for orchestra (2007), Blossoming for string quartet (2007), Lied for flute and piano (2007), Voyage IX Awakening for guitar and strings with percussion (2007), Lied III for violoncello and piano (2007), Lied II for viola and piano (2008), Sakura for marimba (2008), Cloud and Light for shō and orchestra (2008), Stunden-Blumen – Hommage à Olivier Messiaen for clarinet, violin, violoncello and piano (2008), Calligraphy, six pieces for string quartet (2007–9), Chant for cello and orchestra (2009), Voyage X Nozarashi for shakuhachi and ensemble (2009; version for shakuhachi orchestra, 2011), Schneeglöckchen for tenor recorder and koto (2009), Edi for clarinet (2009), Danses imaginaires II for large orchestra (2010), Für Walter − Arc-Song II for soprano saxophone, piano and optional percussion (2010), Woven Dreams for orchestra (2010), Spell for violin (2010), Horn Concerto Moment of Blossoming (2010), Matsukaze, opera in one act (2010), Sternlose Nacht − Requiem für Jahreszeiten for soprano, mezzo-soprano, two narrators, mixed chorus and orchestra (2010–12), Blossoming II for chamber orchestra (2011), Autumn Wind for shakuhachi and orchestra (2011), Singing Garden in Venice for baroque orchestra (2011), Threnody to the Victims of Tohoku Earthquake 3.11 for viola (2011), The Raven, monodrama for mezzo-soprano and 12 players (2011−12), Meditation to the Victims of Tsunami 3.11 for orchestra (2012), Mai, old Japanese dance music for piano (2012), Etude II Point and Line for piano (2012), Nacht Klange for cimbalom (2012), MI-KO for three accordions (2012−13), Concerto for Trumpet and Orchestra Im Nebel (2013), Klage for soprano and orchestra (2013), Distant Voices for string quartet (2013), Ancient Voices − In memory of Wolfgang Schulz for wind quintet (2013), Trio for Violin, Cello and Piano (2013–14), Lost Love Song – Tsurenaki-Hito for voice, bass recorder and string quartet (2014), Drei Engel-Lieder for soprano and harp (2014), Aeolus − Re-Turning III for harp and chamber orchestra (2014), Small River in a Distance for string quartet (2014), Fluss − Ich wollt’, ich wär ein Fluss und Du das Meer for string quartet and orchestra (2014), arrangements of Japanese folk songs.