Motohiko Hamase (濱瀬元彦) is a Japanese bassist, composer and music theorist who has lived two musical lives in sequence and is now living them side by side. He was born on 15 April 1952 in Aichi Prefecture and left Keio University without graduating. From 1976 he worked as a sideman on acoustic and electric bass in the Tokyo jazz and fusion scene, then withdrew from that circuit in the mid-1980s and began releasing solo records built on fretless bass, sequencers and long, slowly turning ambient structures. Those records are what the rest of the world found in the 2010s and 2020s. The jazz is still in them, and he has gone on writing about it, teaching it and playing it.

His own biography says he has played in jazz groups since 1976 under leaders including Hidefumi Toki, Isao Suzuki, Mikio Masuda, Kazumasa Akiyama, Yasuaki Shimizu and George Otsuka. The record trail starts with Suzuki. On 19 and 27 October 1976 at Epicurus Studio in Tokyo, the Isao Suzuki Sextet cut Ako's Dream for Three Blind Mice (TBM-76). Hamase is on bass and electric bass, Suzuki on cello, Kazumi Watanabe and Akiyama on guitars, Tsuyoshi Yamamoto on piano, electric piano and synthesizer, and Akira Doi on drums. The next summer, on 24 July 1977 at the Denen Colosseum in Tokyo, Suzuki's group played "Feel Like Makin' Love" for the festival live set Jazz of Japan Live Under The Sky '77 (Flying Disk), with Hamase on electric bass, Doi, Akiyama and Watanabe again, Masanori Sasaji on Fender Rhodes and Noriko Miyamoto singing.

The end of 1977 was crowded. On 12 October, at Onkio Haus in Tokyo, he played electric and acoustic bass on tenor saxophonist Takao Uematsu's Straight Ahead (Trio Records), a sextet date with Masuda on keyboards, Hitoshi Okano on trumpet, Arihide Kurata on drums and Tatsuji Yokoyama on percussion; its opener "White Fire" was picked up forty years later for BBE's compilation J Jazz: Deep Modern Jazz From Japan 1969-1984. From 1 to 3 December he was the bassist on Masuda's own Moon Stone (Better Days) at Nippon Columbia's first studio, alongside Watanabe, Akiyama and drummer Hideo Yamaki. On 29 and 30 December he played bass on Moritat, the Philips album by the vocalist Minami Yasuda, with Masuda on piano, Kohsuke Mine on tenor saxophone, Hideo Miyata on harmonica, Hisaya Miyagi on violin and Hiroshi Murakami on drums.

He kept that pace into the early 1980s. He is the electric bassist on Isao Suzuki & New Family's Mongolian Chant (Paddle Wheel, recorded 20 and 21 April 1980 at King Records Studio), where Shigeharu Mukai and Toshiyuki Honda are billed as guests. He is credited on Kazumasa Akiyama's Beyond The Door (Flying Dog, 1979) and Noriko Miyamoto's Vivid (Trio Records, 1979). Around Yasuaki Shimizu he played on the experimental pop records Shimizu produced and arranged for, among them Shimizu's own IQ 179 (1981), Tomoko Aran's 神経衰弱 (1981) and 色彩感覚 (1982), and Naomi Akimoto's One Night Stand (1982), a set of swing standards that opens with "On A Slow Boat To China" and includes "Sing Sing Sing". He is also the bassist on a 1982 live album credited simply to a group called Jazz, with Shimizu on tenor saxophone, Masanori Sasaji on keyboards and Yamaki on drums, that plays "Night In Tunisia" and "All The Things You Are"; the same group name returned on a 2004 studio album, also titled Night In Tunisia. Outside jazz he is credited on Pierre Barouh's Le Pollen (1982) and on the soundtrack to Katsuhiro Otomo's Domu (1984), where he plays what Discogs lists as wood bass. In print he published Fretless Bass Technique (Rittor Music, 1980) and Super Mechanical Training for Electric Bass (Rittor Music, 1982).

In 1982 he formed an experimental unit called Lager (ラーゲル), which ran until 1985. Around then he stopped taking session work. Japanese Wikipedia attributes the decision to a sense that his music did not fit what the industry wanted and that few players understood it. He turned to solo recording, and his first records came out on the Shi Zen label: Reminiscence on 25 January 1986 and Intaglio on 25 November 1986, both recorded at Sound Design Studio in Tokyo. On 12 June 1987 he played a live set at Spiral Garden in Aoyama with the pianist and synthesist Toshio Kaji and the percussionist Yasunori Yamaguchi, as part of the Eat Newsic Concert No. 3; Yamaguchi's playing that night led him to invite Yamaguchi into the studio for the next album. That was #Notes of Forestry, recorded at Studio Farm in Tokyo in March 1988 with the pianist Satsuki Shibano and co-produced for Wacoal Art Center by Yoshio Ojima, the first CD on Spiral's Newsic label (32CD-N001). The live set from the year before finally came out in 1993 on Hamase's own Lung label as Anecdote. Technodrome (Newsic, 1993) followed, and it was the first album he made entirely alone, recording, editing and programming everything including the bass on a computer.

The writing runs alongside the records. Bass Line Book appeared from Zen-On in 1987, followed by Blue Notes and Tonality (Zen-On, 1992), which proposes a theory of how the blue note develops and a tonal system for improvisation and composition; in explaining blue notes, he put forward a hypothetical lower harmonic series. He founded a private music school, Lung (ラング), to train working players. Naruyoshi Kikuchi, the saxophonist and writer, later gave the approach the name "Lung method" and praised its importance. In 2013 Iwanami Shoten published his チャーリー・パーカーの技法 (English title Syntax in the Musical Language of Charlie Parker), a structural analysis of Parker's improvisations drawn from more than 600 scores and written from a player's point of view. He also contributed to two lecture books by Kikuchi and Yoshio Ootani: M/D: A Study of Miles Dewey Davis III (Esquire Magazine Japan, 2008) and Albert Ayler at the University of Tokyo (Bungeishunju, 2009).

In 2008 he formed the Motohiko Hamase E.L.F Ensemble, which plays his own compositions in new arrangements and was described on Japanese Wikipedia as a human-powered techno-jazz unit. Kikuchi joined as guest and producer. On 13 April 2010 the group recorded a concert at JZ Brat in Shibuya, released by Airplane Label as "The End Of Legal Fiction" Live At JZ Brat: Hamase on a six-string fretless bass built by Jan Knooren and run through a guitar synthesizer, Rei Shimizu on a second bass and electronics, Katsutoshi Narisawa on piano and synthesizer, Yoichi Okabe on percussion, and Kikuchi on saxophone.

His older records returned to circulation from 2018. Studio Mule in Europe issued new recordings of Intaglio (10 August 2018) and Reminiscence (19 October 2018), played entirely by Hamase on six-string fretless bass, with Kaji on piano for Intaglio. In May 2020 the Swiss label WRWTFWW Records reissued #Notes of Forestry, Technodrome and Anecdote on vinyl and CD, with a numbered box set of 60 signed by Hamase. His official site lists a new mix, Technodrome Variant, in October 2022, and says he resumed live solo shows combining digital and acoustic instruments. In June 2025 he resumed jazz performances with the pianist Toshiyuki Daitoku. A concert at JZ Brat in Shibuya with Rei Shimizu and Yoichi Okabe was billed for 26 August 2026 under the tags ambient, experimental, improvised and jazz. He turned 74 in April 2026.

Hamase's instrument on his later records is a six-string fretless bass built by Jan Knooren, and on the 2010 live album he runs it through a guitar synthesizer. On the 1970s sideman records he is an electric and acoustic bassist working inside the fusion and jazz-funk sessions of the period, under Masuda's electric piano or Suzuki's cello, in sextets and behind a vocal feature. The solo records are a different proposition. They are slow, tonal and built from short repeating cells, and Dean Suzuki, reviewing #Notes of Forestry in Audion (July 1990) and Ear Magazine (April 1991), heard minimalism influenced by Steve Reich, with a Zen-like calm, a less insistent pulse and a more complex, sometimes dissonant harmony that stays tonal. He singled out the title track for its jazz-tinged bass and flute solos set inside strict post-minimal structures.

Technodrome is where he says out loud what he is doing. In his own liner essay he describes it as a response to house music and to recent records by Brian Eno (Nerve Net) and Jon Hassell (City: Works of Fiction), an attempt to express urban consciousness through the repetition of very short phrases and a sense of time that binds rather than develops. He calls the style ambient house. One of its tracks, "End Of Legal Fiction", he describes as aimed at believers in jazz mythology, and the album was the first he made entirely alone. His records have also been compared to those of Jon Hassell and Midori Takada.

The jazz did not disappear. The theory books, the Parker analysis and the Kikuchi lecture contributions are all about improvised language, the E.L.F Ensemble plays at JZ Brat in Shibuya with a saxophonist and a second bassist, and the venue lists his shows under jazz as well as ambient and experimental music. The 2018 Studio Mule re-recordings are catalogued by Discogs under both Electronic and Jazz.