Im In Gun (임인건) is a South Korean jazz pianist and composer who played the piano at Janus, the Seoul club that Korean press calls the country's first regular jazz room run by a Korean, for about 27 years by his own count, and who has released records under his own name since 1989. Korean writers place him between two generations: the Korean Wikipedia article and a 2016 Seoul Shinmun piece call him part of Korean jazz's "1.5 generation", while a 2015 Herald column calls him a leading second-generation musician. His name is also written Im In-gun, with a hyphen, and the Revised Romanization of the Hangul is Im In-geon. His own releases print it as Im In Gun (the form on most of his Apple Music catalogue and a Discogs name variation), as Lim In Gun on Apple Music for the 2015 duo album Assimilation and for his 2018 singles and his 2024 and 2025 releases, and as Ingun Im on the High Resolution Audio catalogue. His birth date, birth year and schooling are not published in any source found. The Herald says he is from Seoul, and he has lived on Jeju since 2013.

The earliest credit found is on piano on the second album of the blues singer Yun Myeong-woon (Jigu Records, JLS-1202240), which Discogs dates February 28, 1989. His own first record came the same year: 비단구두 (Silk Shoes), a nine-track LP on Seoul Records (SPER-081) whose sleeve is dated November 1, 1989. Its notes borrow a line about a brother who promised to bring silk shoes back from Seoul and offer the shoes in place of the brother who never came home. Marie Claire Korea later described it as the first solo piano album in Korea, and the Seoul Shinmun called it the first new-age piano solo album in the country; Discogs files it under Jazz. A 1991 Apple Music listing carries the same nine pieces plus an opener, "평화" (Peace), under the title 평화/그리고 그 후에.

He told the Channel Yes24 interviewer in 2017 that he joined Janus around 1986. The trumpeter Kang Dae-gwan had been playing with him at the Lotte Hotel in Myeong-dong, together with the late drummer Choi Se-jin and the guitarist 목우영, and asked him to take the club's piano chair. The pianists before him, by his account, were Shin Kwan-woong, who had left to lead his own trio, and 이영경. He played there on Saturday nights as the club moved from its Ihwa-dong rooms to the back of Ewha Womans University, then to Cheongdam-dong and finally to the area near Gyodae station. The Seoul Shinmun counts 25 years at the club where he counts 27. The Herald says he played with the first-generation figures Park Sung-yeon, Lee Pan-geun, Kang Dae-gwan, Kim Soo-yeol and Lee Dong-gi and acted as a bridge to the next generation.

His next records came at long intervals. 피아노 연주집 Vol. 2 (Piano Recital Vol. 2, Oasis Record, August 18, 1992) has eight pieces, among them "여행" (Travel). 피아노가 된 나무 (The Tree That Became a Piano) followed on September 23, 2004 with eleven tracks, and 소혹성 B612 (Asteroid B612) on June 19, 2007, again with eleven. In 2010 his "강선생 브루스" (Mr. Kang's Blues) was one of the tracks on the soundtrack of Nam Mu-seong's documentary Bravo! Jazz Life, released by Kang & Music (Discogs release 18446455). Inflection Point (변곡점, April 19, 2011, Kang & Music) came after what the Melon album notes call a period of seclusion, and those notes quote the critics Hwang Deok-ho and Nam Mu-seong from the liner essay; Nam praises the warmth that machines and MIDI programs produce. The Herald says he drew attention in 2011 for using MIDI, which is rare in a music built on improvisation. The tenor saxophonist 켄지오메 is named on two of its tracks, the drummer Kim Yeong-jin (김영진) on three, and the singer 최지훈 is on "생일 축하해".

Park Sung-yeon tried to talk him out of leaving. He decided in 2012 to move to Jeju, she asked him to stay and he waited a year, and in 2013 he played his last Janus night to an audience of two. After the set she gave him an envelope with 50,000 won and called it his severance pay, and he has said he would one day like to write a piece with that title. In 2013 a Mirrorball Music album, 서울하늘, 제주하늘 (Seoul Sky, Jeju Sky), appeared under the billing Im In Gun & Atman; the sources do not say who or what Atman is.

On Jeju he began, late in 2014, a project of music about the island with the bassist Wonsool Lee. It became All That Jeju (올 댓 제주, D Ocean Music, April 21, 2015), a compilation of songs by Jang Pill Soon (장필순, "애월낙조"), Jung Joonil, BMK, Kang Asol, Yozoh, Lua, Cha Eun Joo and Cha Yoon Sub with two of his own instrumentals, "평대의 봄" and "푸른밤 푸른별". "하도리 가는 길" (The Road to Hadori), which Kang Asol sings there, was the first lyric he ever wrote, and the Herald reviewer called the album a gentle, stripped-down return for a veteran. The High Resolution Audio notes say that Lee, who had known him for almost 20 years, joined All That Jeju as producer, and that the two then decided to make a duo record. 동화 (Assimilation, September 17, 2015) has ten tracks, recorded without rehearsal so that the two would, as the album title says, grow alike. EBS Space billed the two for November 4 and 5, 2015 in a program titled 혼자 떠난 여행 (A Trip Taken Alone), with "서울하늘" in the set list.

His best-documented record is 야누스, 그 기억의 현재 (Janus, The Reminiscence, Pageturner, 2016). In 2015 the clarinettist Lee Dong-gi fell ill and Park Sung-yeon, short of money, gave up the club and entered hospital, and he decided not to wait any longer. The album is made of pieces he wrote for the first-generation players, not standards, and it opens with "I'll Remember 이판근", a piece co-credited to Lee Pan-geun, long the club's music director, who supplied only the opening bass notes before he handed the rest to the pianist. Park sings "별빛의 노래", "바람이 부네요" (The Wind Is Blowing) and "길 없는 길", Lee Dong-gi sings "하도리 가는 길" and plays clarinet on "When You Wish Upon a Star", Choi Sun-bae plays flugelhorn on a second version of "하도리 가는 길", and Kim Soo-yeol and Wonsool Lee play "Mr. 김수열" as a tenor saxophone and bass duo. Ten jazz singers, including Malo and Woongsan, sing the chorus on "길 없는 길". Wonsool Lee arranged every track, played bass and produced. A choir version of "바람이 부네요" with about 70 members of the public and 20 jazz academy students closes the album. It came out digitally on August 31, 2016, and as a CD box set with a 52-page booklet on September 7, 2016. The release concert at the Seongsu Art Hall on September 3, 2016 was billed with Park, Lee Dong-gi, Kim Soo-yeol, Choi Sun-bae and Kim Jun, and Park had two hours out of hospital for it. The album was one of six nominees for the jazz album prize at the 14th Korean Music Awards, held on February 28, 2017; Choi Sung-ho's Singularity won it.

After that he kept to a steady pattern of festivals, piano solo concerts and small releases. The Korean Wikipedia article lists a 비단구두 piano solo concert in 2017, the Seoul Forest Jazz Festival in 2017 and 2018 and the Cheongnamdae Jazz Tonic festival in 2018, and a Marie Claire Korea festival guide for autumn 2018 billed him with the singer Jang Pil-soon at Seoul Forest on October 6 and 7, noting that both live on Jeju. He re-recorded all nine pieces of 비단구두 for Pageturner on January 29, 2018. Single releases followed with Kim Mok-in ("군산추억", March 2018), BMK ("그대여 어제는 왜 그리 취했나요", April 2018), Kim Doo-soo ("저무는 길", August 2018, a piece Discogs credits him as composer of on Kim's 2023 album 류목 Driftwood) and Lee Na-rae ("나의 가을", October 2019). Rhapsody in Gunsan (랩소디 인 군산, D Ocean Music, November 5, 2020) has seven pieces. By his own account in 2017, Gunsan was the city where a visit to a younger artist first gave him the idea for the Janus album.

His recent output is smaller. He is credited as a featured artist on Seulgi's single "You're My Joy and Luck" (April 3, 2024), "Birthday" appeared on Mirrorball on November 24, 2024, "Gelato" on August 16, 2025, and a two-part EP, 누군가 어디에서 나를 기다리면 좋겠다 (I Wish Someone Was Waiting for Me Somewhere), on October 4, 2025. He is among the colleagues who appear in the documentary Diva Janus, about Park Sung-yeon and the club, which opened in Korean cinemas on October 22, 2025. Melon lists his agency as Pageturner, a management company whose other artists include Wonsool Lee and which runs the Round Midnight concert series.

He plays slowly and melodically, with simple harmony and a lot of space. A High Resolution Audio biography says that he sets out to narrate ordinary life as if in a film or novel, and that he describes his music as simple and ordinary. An EBS Space preview from 2015 calls his playing lyricism itself, closer to new age than to flashy modern jazz, and says he keeps a distance from the showier side of jazz. The release notes for the Janus album, carried by the Seoul Shinmun, say it is the most strongly jazz-coloured of his records while keeping his lyricism and folk feeling. In the liner notes of Inflection Point he called himself a hitchhiker with jazz as his pack who wants to travel anywhere.

Much of his work is written for singers or in collaboration with them. He wrote lyrics for the first time for "하도리 가는 길" and then for Park Sung-yeon's songs on the Janus album, and he has worked with folk and indie singers (Jang Pill Soon, Yozoh, Kang Asol, Kim Mok in) as readily as with jazz players. Place runs through his titles: Seoul Sky, Jeju Sky, All That Jeju, Rhapsody in Gunsan. No source found names the pianists or records that shaped him, so that is left open here. His standing as a jazz musician rests on his years as a regular pianist at Janus, 25 or 27 of them depending on the account, and on records such as the Janus album, which the Korean Music Awards considered in its jazz category.