Prelude (프렐류드) is a South Korean jazz band led by the pianist Heean Ko (고희안). It began in Boston among students of Berklee College of Music, made its first album for the Korean branch of Sony BMG in 2005 and has worked mainly in Korea since, where it still plays on Sundays at the Seoul jazz club Janus, the stage of its debut. It is a quartet today: Ko, the saxophonist Richard Rho, the bassist Jinbae Choi (최진배) and the drummer Woongwon Han (한웅원). Most of its members are Korean or Korean-American, its records come from Sony Music Korea and Mirrorball Music, and its concerts since 2006 have been mostly in Seoul and other Korean cities. The band prints its name as Prelude, in lower-case lettering on several of its covers, and Discogs splits its releases across entries named 프렐류드, Prelude (16) and Prélude. The releases that can be named and dated number thirteen, from Croissant in 2005 to JZNR Vol. 1 in 2025; the later ones increasingly set Korean folk song to jazz.

Sources disagree on the start date. The Korea JoongAng Daily wrote in January 2006 that six men met as music majors at Berklee and formed the band in 2002, while the Yonhap news agency quoted Ko as saying the team was formed in 2003, and Korean newspapers and the release texts have used 2003 ever since. The name came from Rho, who lived in the United States and drove a car called a Prelude; Ko told Hankyoreh in 2021 that a brainstorm of names had produced something like "jazz ambassador," which did not stick, and that Rho's suggestion won because it suggested a beginning and an overture to Korean jazz. The six founders were Ko, the alto saxophonist 최원석, the bassist Jinbae Choi, the saxophonist Charles Lee, Rho and the drummer Abraham Lagrimas Jr. The JoongAng Daily wrote that three of them were born and raised in the United States and three came from Korea, and that Lagrimas was from the Philippines; Yonhap called him American and said the other five were Korean or Korean-American. The JoongAng Daily called Ko the leader and pianist, and the first album's release text describes the sextet as a piano, bass and drums trio with two tenor saxophones and an alto.

The first album was Croissant, released on December 5, 2005 by Sony BMG (SB30112C). Its release text says it was recorded and mastered at a jazz studio in Boston and that the band had played Seoul clubs and appeared on EBS broadcasts in the previous summer and winter; its eleven tracks mix standards such as "Georgia On My Mind" and "Four Brothers" with "Island Baby," the children's song 섬집아기. The vocalist on "Croissant" and that song was 크리스티 블룸, a friend from the Berklee years, according to the release text of the fifth album. The JoongAng Daily reported that Croissant sold more than 1,000 copies in Korea within a month of a month-long concert series, a high figure for a young jazz market. Ko told Yonhap that he had taken a demo CD to the Blue Note club in Manhattan as soon as the band formed, and that the club liked it but would not book a band with no album behind it; after Croissant the booking was confirmed. Yonhap called it the first time a band led by Koreans would play there and gave April 2006 as the date, while the JoongAng Daily gave May. In a 2008 interview with the Busan Ilbo, Ko said that the Blue Note stage booked for 2006 had been set and then cancelled.

The Seoul years followed quickly. The second album, Breezing Up (Sony Music, April 10, 2007), carried ten pieces, and its release text quotes critics from the monthly Jazz People and elsewhere praising its energy and its tighter writing. That year the band played the Jarasum International Jazz Festival, and in May 2008 it was billed for the Seoul Jazz Festival's Funky Groove Night with The Crusaders, according to the Korea Times. The alto saxophonist left after the second album, which made the band a quintet from the third, Prelude (April 10, 2008), whose ten pieces include themes from the films Once and Howl's Moving Castle and originals such as "Seascape" and "Sweet Morning"; a Christmas Edition added four carols on November 25, 2008, and the band gave a Christmas concert at the Sejong Center's M Theater that December. Both Sides of Prelude came out on November 11, 2009, and the band was invited to Los Angeles for the first Asian-American Jazz Festival that month. In early 2010 Seoul Shinmun reported that Charles Lee had left for a solo career and further study and that the saxophonist 김지석, a University of New Orleans graduate, had replaced him; Han stood in for Lagrimas, who was living in the United States, at the Valentine's Day concerts of February 13 and 14 at the Seoul Arts Center. Lagrimas still plays the ukulele solo on the next album's title song, according to its release text.

5th Movement (November 12, 2010) was the first Prelude album to put a singer in front. Its release text names 허소영, then a rising vocalist in Jazz People's estimate and now the subject of a profile as Soyoung Heo, on six songs, and says the fourteen tracks hold eight new Ko originals, six of them in both vocal and instrumental versions. The title song "Piccadilly Circus" came from Ko's visit to that part of London for a concert, and its music video is set in Britain. Day Off, the sixth album, followed on February 23, 2012 with the singer-songwriter 오지은 on two songs and the sori singer Jeon Young-rang on "Arirang," and a release concert on March 18 at LG Arts Center in Seoul. Beyond (November 15, 2013) was the seventh and marked ten years; its release text says the band gave two regular concerts a year, that all of its members took first place for their instruments in the 2013 Readers Poll, and that it had appeared in an independent film, Jazz Quartet, directed by 유대얼 and invited to a film festival in Jecheon.

The next record was Fly In (January 29, 2014, Sony Music), a project album with the Gyeonggi minyo singer Jeon Young-rang (전영랑) of eleven folk songs including "태평가," "밀양 아리랑" and "비나리." Discogs credits Ko on piano, Rho on saxophone, Choi on bass and Han on drums, with Ko and Choi as composers, and a Gyeonggi newspaper that March counted four members: the same four who play today. Hankyoreh reported in 2021 that Ko, who had worked with the saxophonist Lee Jung-sik, and Jeon, who had worked with the samulnori founder Kim Deok-su, got to know each other through joint concerts of those two from 2005, and that Jeon was startled when the band recorded the first album without rehearsing together, since jazz players prepare alone. The band was booked for Tribowl in Incheon on April 13, 2014 with Jeon as guest, for a Christmas concert at the Sejong Center's chamber hall on December 23 to 25, 2014 and, with Jeon again, for the National Gugak Center's Brilliant Dissonance series on May 9, 2015. In December 2016 it re-recorded its Christmas album, eight years after the first, as Holiday.

In 2017 the band joined the sori singer Lee Heemoon (이희문) and the vocal duo Nom Nom (놈놈) for 한國男자, released March 9, 2017 and known in English as Korean Men. The programme began as a show for the National Theatre of Korea, and on September 24, 2017 the quartet played it with Lee in the Elgar Room of the Royal Albert Hall in London as part of the K-Music Festival. London Korean Links reviewed the evening warmly, noting the quartet's white double-breasted suits, Rho acting as host and an encore of "Gangwon-do Arirang" in a swing arrangement. A second volume, 한국남자 2, followed on June 20, 2020. Six months later came Fly-In Vol. 2: Modern Jass (December 18, 2020), a second record with Jeon Young-rang on the "jass" of 1930s and 1940s Seoul, the mix of new folk song, comic song and imported swing that Choi described to Hankyoreh; its title song "어느 사월에," a slow waltz, is by Ko. A recital show at the Sejong Center's M Theater was scheduled for October 10, 2021.

The band kept playing through the 2020s. Videos titled as a 2023 Prelude Real Jazz Concert were filmed by PRM Idealab, and a Money Today preview billed the band with the former Wonder Girls singer Sunye in Dongtan for October 25, 2024, adding that Prelude had made eleven albums in twenty years. JZNR Vol. 1 (June 20, 2025, Mirrorball Music), a six-song record with the young seodo sori singer Yegyul (예결), came five years after the previous one; its title song "양류가" is a jazz-funk arrangement and "는실타령" a jazz waltz, and the release text credits the music of the first three songs to Han and Yegyul. A coffee concert with Jeon Young-rang at the Incheon Arts Center was scheduled for July 15, 2026, and on October 15, 2026 the band opened the Curtain Call Garden at the Sejong Center, where JoongAng Ilbo described it as a 23rd-year band that still plays Sundays at Janus.

What is not known is a good deal. No band website or press biography turned up, and no award for the band as a group was found. The sources name the players on Fly In and in the press reports of each period, but the other albums are not credited with full personnel. Counts differ: the 2016 release text counts seven regular albums and one project album, and the 2024 Money Today report counts eleven, while the list in the Full Discography names thirteen titles with the Christmas Edition and Holiday included. Release dates also differ by a few days between streaming services, and the dates here follow Genie and Bugs.

Prelude plays accessible, melodic mainstream jazz, written largely by Ko, and has said so itself. In early 2006 Rho told Yonhap that the band did not want an orthodox style that would weigh on listeners, because players who are not Black would only sound unnatural imitating Black American jazz, and that they wanted music both players and audience enjoy; the alto saxophonist Choi Won-seok called it Korean-style jazz in the same interview. The release text for Croissant describes a piano trio joined by two tenor saxophones and an alto, which gave the sextet the dense interplay of a small group and, at times, the brass sound of a big band, and Charles Lee told Yonhap that the three saxophones let it shrink to a trio or a quintet. In the quartet of recent years a single saxophone, Rho's tenor and soprano, carries the front line beside Ko's piano.

The repertoire mixes film themes, standards, originals and Korean songs. Prelude includes "Falling Slowly" from Once and the theme of Howl's Moving Castle, Both Sides of Prelude Piazzolla's "Tango Apasionado" and the theme of Woody Allen's Everyone Says I Love You, and Beyond a cover of a song by the Korean group Haebaragi. The release text for Prelude hears the elastic energy of the Pat Metheny Group in "With Me." From Fly In onward the folk material takes over. The JZNR release text says the band thought from its student years that Korean songs suit jazz because both are sung and played with improvisation and the audience's response, and the band arranges and recomposes the songs rather than laying them over a jazz backing. Bugs files its regular albums under jazz and the project records under gugak crossover, with JZNR Vol. 1 under gugak and indie pop as well, which is why the crossover tag sits beside the mainstream one here.