Sun-Ken Rock (Japanese: サンケンロック, Hepburn: Sanken Rokku) is a Japanese manga series written and illustrated by Boichi. It was serialized in Shōnen Gahosha's seinen manga magazine Young King from April 2006 to February 2016, with its chapters collected in 25 tankōbon volumes. The manga has been digitally available in English by JManga (2012–2013), Crunchyroll (since 2014), BookWalker (since 2015), and Manga Planet (since 2020). Kodama Tales has licensed the manga for print publication in English, with the first volume set to be released in 2026. The story revolves around Ken Kitano, a man from an upper-class family that was orphaned young due to his family's involvement with the yakuza; he became a highschool delinquent known for fighting. The only thing that motivates him to take action is through his romantic affections for a classmate, Yumin. After learning she decided to move to Korea to become a police officer, Ken left his life in Japan behind and tried to follow in Yumin's footsteps; due to unforeseen circumstances, he incidentally becomes the head of a local gang and tries to hide it from Yumin. As the leader, the gang is renamed the "Sun-Ken Rock Group". At first, the gang only consisted of few members and did not even have a base. As the story progresses, the Sun-Ken Rock Group becomes bigger as they recruited new members and take over other gangs' territories and investments. The Sun-Ken Rock Group acquires an MMORPG company, a large casino, one of the biggest television media companies in Korea, as well as garnering political favors (making them the most powerful gang in Korea). However, throughout all of this, Ken has done his best to evade revealing himself to Yumin as a gang leader as she despises gangs. Ironically, Yumin was groomed to become an advanced plant in Korea to help her yakuza group lay the foundations to expand their hold into South Korea; due to Yumin's refusal to join the "family business", their plans were stalled as various members either tried to take her back to Japan or try to get her back into yakuza control. In between Ken's rise, he and Yumin got closer and Yumin started to have feelings for Ken. However, things were always complicated by the interference of either Ken's gang activities and/or Yumin's yakuza connections. The turning point in the story is when Yumin is kidnapped by her own group and Ken is exposed as a gang leader in his attempts to rescue her from his greatest rival, Kim Ban Phuong (a Vietnamese-Korean that has a vicious score to settle with Ken).