Sangjin Lee (이상진) is a South Korean bassist who plays double bass, electric bass and fretless bass, and who since 2024 has been the bass half of the YL Jazz Trio with the pianist Yang Junho (양준호). The Hangul 이상진 appears on his Bugs artist page, on the front of the trio's third album, which prints 양준호, 이상진 and 이광혁 as the three names, and in the Korean text of Kyunghyang's July 1, 2026 report on the Jarasum Jazz Festival lineup. The liner credits of the trio's first album print his name as Sangjin Lee, which is the form used here; the Kyunghyang report writes it Lee Sangjin, and a Revised Romanization of the Hangul would be Lee Sang-jin. His birth date, birthplace, training and early career are not published in any source found. Bugs gives his nationality as South Korea, lists him as a solo artist who debuted in 2015, and tags his music as jazz.

His first release was Wayfarer (October 6, 2015, distributed by Purplepine Entertainment). Its Bugs notes introduce him as the bassist of the jazz band Lunar-Hill and the neo-soul band Retro Twang, now releasing his first record as a soloist. It has four tracks and runs about 15 minutes: "Entrance", "7th Lover", "No.4" and "Wayfarer". The notes say he took on composing, sequencing, programming and production himself and wanted a more experimental, forward-looking sound than the usual jazz solo album. Credited with him are Gong Jeong-hun (공정훈) on electric guitar throughout, Cha Seung-yeop (차승엽) on piano on the opening track and Yoo Young-ha (유영하) on synthesizer on the title piece, with mixing and mastering by Im Min-su (임민수). Bugs files it under acid jazz and electro jazz/nu jazz. Lunar-Hill is spelled Luna-Hill in another Bugs note, and nothing more about that band was found.

Retro Twang started the same year. The notes of its 2019 EP say it began in 2015 with the bassist Sangjin Lee and the keyboardist Yoo Young-ha as its axis, and the notes of its first single name the vocalist Yoon Sol (윤솔) as the third member. The single "Sometime" came out on May 7, 2015, described as a blurred border between jazz, pop and neo-soul, followed by "Insomnia" (불면증, August 18, 2015) and "Hey Now" (September 9, 2015). A fourth single, "티격태격" (April 25, 2016), introduced the vocalist Mi So-young (미소영) and the pad drummer Park Gwang-hyeon (박광현), with Lee on bass guitar, and was announced with a concert at Blue Light Hall in Hongdae two days later. A self-titled EP followed on June 2, 2017: eight tracks, two of them instrumental versions, under the slogan "emotional electronics" and a stated aim to play everything live with no backing tracks. Its notes say the band had by then played the Ulsan Jazz Festival, the Bukchon Music Festival and Seoul Music Week. The last release found is the EP Plug In (May 16, 2019), five tracks with the saxophonist Gu Min-sang (구민상) newly in the band, which its notes call a trio of jazz and neo-soul; Lee composed the title piece "Get Started" and plays bass on the tracks that list personnel, with the vocalist Hyeon Jin-ju (현진주) as a guest on "Giant". Bugs files the 2015 to 2017 releases under R&B/soul and indie and the 2019 EP under jazz. No Retro Twang release after 2019 turned up.

Alongside the band he released a run of solo singles between 2016 and 2021, most of them recorded largely alone. "Alien" (August 16, 2016) was composed, arranged, played on keyboard, bass guitar, electric guitar and rhythm programming, and mixed by him as a one-man band. "Analog Brain" (April 21, 2017) is a short instrumental led by an analog synthesizer and a bass melody, which the notes place in the sound of the 1970s and 1980s, and Bugs tags it fusion jazz. "Smooth Pub" (May 19, 2017, called his seventh single), "Bittersweet" (January 30, 2018, his eighth) and "A Woman in Blue" (January 28, 2019, his ninth) follow; the first is a smooth-jazz piece with a short fretless bass solo and Gong Jeong-hun on guitar, the second a synthesizer-heavy groove, and the third an acoustic piece for piano, organ, acoustic guitar and fretless bass, all played by him. The Bugs page lists seven releases in total, so the singles his notes count are not all on it. Bugs lists Alien Lab as the production company on his singles from 2017 to 2021, on the 2019 Retro Twang EP and on the trio's 2026 album. The latest solo piece found is "머무른 시간들" (May 31, 2021, about 6 minutes), a quartet recording with Oh Hwan-hee (오환희) on piano, Gu Min-sang on saxophone, Lee on double bass and Lee Gwang-hyeok (이광혁) on drums, recorded at Velvet Sound; its notes describe a quiet, melodic bass line that opens into a saxophone solo, and credit the photograph and artwork to him.

The YL Jazz Trio is his work in the piano-trio tradition. Bugs describes it as two artists from the jazz scene who joined as the YL Jazz Trio, pianist Yang Junho and bassist Sangjin Lee, and Kyunghyang's 2026 report says the pair's shared musical understanding was formed through their work with the Seoul Jazz Quartet, Vinalog and Sinchon Blues, without saying which of them played in which. The trio's first album, Travel (November 23, 2024, ten tracks, about 67 minutes, distributed by Soundpress), was recorded at E-UM Sound studio. Yang, credited as Junho Yang, wrote nine of the ten pieces; Lee wrote "Cabin in the afternoon", and the two are credited together as producers, executive producers and photographers. The drums are Sungjae Jung (정성재) on most tracks and Bonjun Ku (구본준) on "West Sea" and "Sing a Peace", with the violist Jeong Min-gyeong (정민경, billed Viola-lora) and the flutist Hyosung Cho (조효성) added on two tracks. The notes describe a record about missing travel, from a trip taken on impulse to the last trip before the pandemic and life itself as a journey, and the last line calls it a journey made with Sangjin.

The second album, am 2:00 (September 25, 2025, ten tracks, about 63 minutes), is billed in its notes as emotional jazz built on harmony and melody, made from the moods of two o'clock in the morning, and it was released with support from Gangwon Special Self-Governing Province and the Gangwon Cultural Foundation. Lee plays bass on all ten tracks; the drummers rotate, with Lee Chang-hoon (이창훈) on the first four, Sungjae Jung on "Airport" and the quintet version of "Mauritius", and Lee Gwang-hyeok on "Iberia", "am 2:00" and "Madrid Run", and no drummer is listed for the last piece, "바닷마을". "Gloria's Step" is the one outside composition, credited to Scott LaFaro. "Airport" features the Tenerife duo Socos Dúo, the cellist Ciro Hernández and the marimbist and electronics player César Martín, who are credited as co-composers; a Spanish regional paper reported on May 22, 2025 that the duo would record with the YL Jazz Trio at the EUMSOUND studio in Seoul during a Korean tour from May 25 to June 1, and the album's credits name E-UM Sound as the studio. A video on the trio's channel, posted on September 9, 2025 and described as sent in by an audience member, is titled as a concert in Tenerife, day 3, playing "Travel". Apple Music lists a five-track, 37-minute album credited to Socos Dúo and the YL Jazz trio, Isla 자유, released on November 14, 2025 (copyright Vector de Ideas); no personnel is listed there.

On The Road (September 30, 2026, ten tracks, about 66 minutes) is the third album and, according to its notes, the first on which Lee Gwang-hyeok joins as a member of the trio rather than a rotating drummer; the notes say every piece is for the plain trio and that it aims to fill by leaving things out. It was again supported by the Gangwon province and its cultural foundation. Lee plays contrabass on most of it and fretless bass on the opening track, "Ninos en la Playa". He wrote two pieces himself, "The Scene on the Street" and "One Step Forward", and the drummer wrote "Blue Rain"; Yang wrote the rest. The credits give the photography to Lee. The trio was named in the first lineup of the 23rd Jarasum Jazz Festival, announced on July 1, 2026, for the festival that ran from October 9 to 11. Which day and stage they played is not listed in the sources found.

The pianist is very probably the Yang Joon Ho (양준호) profiled on JazzProfiles.com, the pianist of the Seoul Jazz Quartet: Kyunghyang names the Seoul Jazz Quartet for the pair, and the drummer Lee Chang-hoon on am 2:00 is the drummer of that pianist's own trio on his 2008 and 2014 albums. No release credit names both bassists, so the link rests on those two matches. The name Sangjin Lee is common in Korea, and the identification of the bassist rests on the Bugs credits, the album jackets and the Kyunghyang report. He is alive and active as of October 2026, but nothing is published about his age, schooling or teachers.

Nothing in the sources found names his teachers or the players he follows, so this section describes only what the releases and their notes say. In the trio he works in a lyrical, restrained piano-trio language: the group's slogan is jazz of feeling built on harmony and melody, the second album's pieces are described as moods felt at two in the morning, and the third album's notes speak of emotion kept moderate and melodies kept disciplined. His own pieces for the trio are few: "Cabin in the afternoon" on Travel and the two compositions on On The Road.

His solo and Retro Twang work sits in a different place. The singles lean on analog synthesizers, drum machines and layered overdubs, with the bass carrying the melody, and Bugs files them under acid jazz, nu jazz, fusion jazz and smooth jazz; the 2015 album's notes call the approach experimental and future-facing. A Woman in Blue (2019) and the 2021 quartet piece "머무른 시간들" are acoustic and melodic, the second with a saxophonist and a drummer. Retro Twang paired neo-soul vocals with synthesizers under a "play it live" rule, and moved toward jazz when it became a saxophone trio in 2019.