Junichi Yamamoto, born December 19, 1985 in Fukuoka Prefecture, is a Japanese anime director, animator, and writer. He is also known by the alias YamaGEn. Yamamoto enrolled in Kyushu University's School of Design in 2005, where he studied design, live-action filming, drawn animation, and 3D CG. He later entered the graduate school of the same university in 2009. During his university years, he created original animations and accepted commissioned work. After graduating, he founded and became the representative director of Najima Studio, working as an animation artist and video director. His early works include the short films Memory (2009) and Anemone (2011), a story based on Alice in Wonderland. Yamamoto holds an 8th dan in calligraphy, a discipline he practiced alongside drawing as a child.

Yamamoto is credited as the original creator for the anime Nekketsu Jinmen Inu: Life Is Movie, a three-episode original video animation released from July to September 2014. For this project, he served as director, scriptwriter, original character designer, chief animation director, and key animator, among other roles. The series, produced by CoMix Wave Films, follows a NEET detective who is a human-faced dog. His authorship of this original work is verified through production credits.

Beyond his original creations, Yamamoto has extensive experience as a series director and episode director on numerous adaptations. He was the series director for titles such as More Than a Married Couple, But Not Lovers (2022), Why Raeliana Ended Up at the Duke's Mansion (2023), Haigakura (2024), Anyway, I'm Falling in Love with You (2025), and Maebashi Witches (2025). His directorial work often extends to storyboarding and directing opening and ending sequences for series like Soaring Sky! Pretty Cure, Yohane the Parhelion, and Is It Wrong to Try to Pick Up Girls in a Dungeon? III. He has also contributed storyboards and direction for episodes of popular series including Summertime Render and the 2022 remake of Urusei Yatsura. His early career included work on the film Your Name in 3D CG.

Yamamoto's artistic identity is informed by his background in both 2D and 3D animation, as well as live-action filmmaking. In an interview, he described a childhood practice of copying manga and deconstructing films to understand their structure, a method he applied to works by directors Shunji Iwai and Mamoru Hosoda. He has expressed that a core motivation for becoming an animation creator is the belief that films and anime ultimately provide hope, regardless of how bleak the world may seem. He is also noted for his work on music videos and short-form animation, demonstrating proficiency in concise visual storytelling.

Yamamoto's industry significance lies in his versatility and his successful transition from independent short films and music videos to directing major television anime series. His involvement in a wide range of projects, from original shorts like POKÉTOON to high-profile adaptations, showcases his adaptability and technical competence in both 2D and 3D animation production.