Kim Dae Hwan (김대환) was a South Korean percussionist, one of the founders of free music in Korea. He was born in 1933 in Incheon and played in military and American-base bands, in the first Korean rock groups of the 1960s and early 1970s, and from 1978 in the Kang Tae Hwan Trio, which Korean Wikipedia lists as the country's first free jazz group. In his later years he took the artist name Heugu (흑우, written 黑雨, "black rain"), played a drum set of his own design with six sticks, performed in Japan so often that Japan became his main audience, and became equally known as a micro-calligrapher who wrote the Heart Sutra on a single grain of rice. He passed away on March 1, 2004. His free-music records as leader or co-leader run from 1993 to 2025, and most of the recent ones are concerts recorded in Japan in the 1990s and released long after the fact.

Seoul Shinmun's 1998 profile and a chronology printed with it give the outline of his early life. He joined the brass band of Dongsan Middle School in Incheon in 1946 and began playing drums, and served in the Air Force band from 1953 to 1957. From 1961 he played on the American Eighth Army stage in Seoul, where, the paper says, he worked with the composers Lee Bong-jo (이봉조) and Gil Ok-yoon (길옥윤) and formed a jazz club with the guitarist Shin Joong-hyun, the figure usually called the father of Korean rock. Korean Wikipedia lists him as drummer of Shin's band Add 4 in 1964, then of the groups Club Date (1968), Questions (1970) and the Kim Trio (1971). A live recording of Shin Joong-hyun and Questions at the Seoul Civic Center in 1970, "Funky Broadway", with Kim on drums, appears on a 2011 digital EP of Shin's music. He took part in the Vietnam War from 1968 to 1972, and the patron who later ran a museum in his name recalled hearing him lead a band called Koreana on a troop-entertainment tour there. In 1972 the label Asia Record issued a rock LP billed to Kim Dae Hwan and the Kim Trio Band, eight of whose ten songs, Discogs notes, are taken from an album by the Japanese drummer Jimmy Takeuchi. In 1975 he became the first president of the Korea Group Sound Association, and his patron said that Shin Joong-hyun and the singer Cho Yong-pil regarded him as the elder brother of Korean group-sound music.

The turn to free music came in the late 1970s. According to Seoul Shinmun, after more than a decade of conventional drumming he realized that every beat could be gathered into a single beat and that one stroke could complete a piece of music, and that insight led him away from his surroundings. In 1978 he joined the alto saxophonist Kang Tae Hwan and the trumpeter Choi Sun Bae in the Kang Tae Hwan Trio. Sisa Journal's 2004 feature on him calls Kang his maternal cousin (외사촌) and says that, orphaned young, he grew up in Kang's household; Discogs and Korean Wikipedia's article on Kang also describe the two as cousins. Weekly Hankook's 2002 profile of Kang says the trio began at the experimental arts space Gonggan Sarang in Seoul and counts 76 performances between 1978 and 1986, when Kang proposed stopping because the group had run out of new ideas; it also says that in 1985 the trio became the first Korean jazz group invited to Japan. A Korea JoongAng Daily report of May 2004 credits Kang, Choi and Kim with starting Korea's avant-garde scene in the 1970s, at a time when, the paper wrote, such players worked construction jobs by day and played at night, and a state security agency refused Choi permission to perform. The three played together again in Tokyo in 1988, in the line-up billed as the Seoul Free Music Trio: it is the opening track of Kang's Korean Free Music (Yeh Eum, 1989), recorded on June 23, 1988 at FM Tokyo Hall, and a trio set from Shinjuku Pit Inn on July 5, 1988 is on Kim's own Like A Dew Also Like A Thunder (2004). The trio reunited in Seoul at Buam Art Hall on August 30, 2002, its first concert together in five years, according to Weekly Hankook.

From the mid-1980s his main audience was in Japan. His patron said he played more than 100 concerts a year there, and Seoul Shinmun's chronology notes that he began performing on Japanese stages in 1985. Seoul Shinmun also says he played in Tokyo with the American trumpeter Wadada Leo Smith and the pianist Yosuke Yamashita; the second of those is documented on record. The chronology lists a first record, Heugu (Black Rain), issued in Japan in 1991 with a launch concert at the Hakjeon Little Theatre in Seoul. Discogs gives its recording as May 25, 1991 at Sound Valley Studio in Tokyo, two long pieces and an encore with the haegeum player Kang Eun Il, and the album was reissued in Korea by Ene Media in 2003. On December 3, 1991 he recorded Black Roots at Yaeum Hall in Seoul with Yamashita, the saxophonist Kazutoki Umezu and Kang Eun Il, a program of "My One And Only Love", "Afro Blue", "Naima", "Arirang" and "My Favorite Things" that Nices released in 1993. The same year he played at a free-jazz festival billed as Black Beat, in Seoul and at Suntory Hall in Tokyo, and he played percussion in Butch Morris's Conduction #50, conducted at P3 Art and Environment in Tokyo on March 5, 1993 and issued in the 1995 New World Records box Testament: A Conduction Collection, alongside the bassist Motoharu Yoshizawa and the turntablist Otomo Yoshihide.

The promoter Takeo Suetomi of Hofu, Yamaguchi, recorded much of what followed. At Suetomi's Cafe Amores, Kim played a duo with Yoshizawa on September 8, 1993 and, on August 10, 1995, a trio with the tenor saxophonist Mototeru Takagi and Choi. In 1994 he played at Gallery MAI in a quartet with Choi, the saxophonist Junji Hirose and the drum master Shonosuke Okura. In Tokyo on June 12, 1995 he was the percussionist in the Choi Sun Bae Quartet with Hirose and Yoshizawa, and on November 26, 1999 he and Choi recorded a duo at the Aspirante room in Hofu. Of these the first to appear was Live "Okidoki" (Chap Chap Records, 1998), a Yoshizawa album whose second track is the Yoshizawa and Kim duo. The rest waited: Seishin-Seido (2022), Korean Fantasy (2023), Echoes Of Empty (2024) and Way Of The Breeze (2025) are all archival recordings from the 1990s. His other Japanese credits include the 2012 DVD Landscape On The Way To Sleep, with the butoh dancer Tomoe Shizune and Yoshizawa, and Like A Dew Also Like A Thunder, which gathers solo, duo and trio tracks recorded between 1988 and 2001 and brings in the pianist Yoriyuki Harada, the guitarist Kazumi Watanabe, Yamashita, Kang Tae Hwan and Choi.

Kim's other art was micro-calligraphy. The Seoul Shinmun chronology dates the start of his fine-writing work to 1968, the completion of the full text of the Heart Sutra on a grain of white rice to 1985, and Guinness World Records recognition to 1990; the paper counts the characters at 283, while one jazz blog says 346. He used the name Yeosu (如水) for calligraphy and Heugu for music. The paper describes a strict routine: he rose at four in the morning for the fine writing, drummed in the afternoon at a practice room in Insadong, and kept to eight hours of practice a day even on tour. He rode a custom Harley-Davidson, used its exhaust pipes as an instrument in performance, and the chronology lists the launch of a riders' group, the Asia Riders, in 1997. Korean Wikipedia lists him as a former professor in the percussion department at Chung-Ang University and records an honorary doctorate from Hansung University. His own book, Practice Was a Majestic Path of Seeking (연습은 장엄한 구도의 길이었다, Hyeonamsa), is named by Seoul Shinmun in 2005. A museum in his name, in the Insadong room that the shop owner Yoo Jae-man had provided him for practice and display from 1989, opened in 1994 according to the paper's chronology.

He passed away on March 1, 2004. Korean Wikipedia and Wikidata give the date; the Newsis news agency, writing on March 29, 2004 of a tribute concert planned for April 6 at the club Once in a Blue Moon in Cheongdam-dong, Seoul, called him a master of percussion who had died on the first of the month. Nine first-generation jazz players were announced for it: the drummer Choi Se-jin, the trombonist Hong Deok-pyo, the percussionist Jo Sang-guk, the clarinetist Lee Dong-gi, the saxophonist Kim Soo-yeol, Choi Sun Bae, the pianist Shin Kwan-woong and the vocalists Kim Jun and Park Sung-yeon, with the first half given to Shin's big band. Sources disagree on his age: Discogs and a bio quoted by a record shop say 70, and Korean Wikipedia, counting in the traditional way, says 72. Seoul Shinmun reported in July 2005 that his supporters had held a national percussion competition in his memory in March of that year, one year after his death, and planned to release some 1,000 live recordings on CD and to build a memorial hall with Japanese backers.

His music has kept returning. Jazz Tokyo's Takehiko Ono reported on the Kim Dae Hwan Memorial Japan-Korea Friendship Concert, held at Gallery MAI in Hofu on May 25, 2024, 20 years after his death. Choi Sun Bae came from Korea for it, and the line-up included the drum master Shonosuke Okura, the voice-and-guitar player Yuki Saga, the Korean percussionist Kaori Komura and the German reed player Alfred Harth; Suetomi organized the evening. Okura's Iyasaka, Dedicated To Kim Dae-Hwan (Chap Chap Records, 2026) includes recordings from that evening.

Seoul Shinmun described the drum set he built as a single large drum struck with six sticks, an idea that replaced his early arrangement of gong, cymbals, rototoms and a big drum played together. Korean Wikipedia puts it as six sticks held across ten fingers, and calls him a master of percussion for it. His own account of the music, relayed by the paper, was that all beats can be gathered into one. Discogs lists his equipment on Black Rain as rototoms, cymbals and traditional Korean percussion, and the Squid's Ear describes Korean Fantasy as a set in which he plays traditional Korean drums in a "one beat" style against Choi's trumpet. The haegeum player Kang Eun Il is his partner on Black Rain and Black Roots; a jazz blog that reviewed Black Rain in 2008 describes the haegeum weeping above a very quiet drum sound.

The Korea JoongAng Daily described Seoul's free music in 2004 as improvisation that opposes written scores and often carries a strong element of performance art, and Kim's career fits that description. He came to it from rock and group-sound drumming, and he treated cymbals, rototoms, large Korean drums and a motorcycle's exhaust pipe as sources of the same kind of sound. Free Music Moogu, an undated solo set whose tracks are listed as Earth Sound and Harley Pipe Sound, shows how far he went from conventional drumming. At the same time the Japanese recordings place him inside jazz: his partners were Yamashita, Umezu, Yoshizawa, Takagi, Hirose, Choi and Kang, and Black Roots is a program of "Afro Blue", "Naima" and "My Favorite Things". Discogs files his main releases under free jazz and free improvisation. His earlier rock records are a separate chapter, and are listed with the discography.