|Kanji:||三原 雄一（みはら ゆういち）|
|Manga Debut:||Chapter 34|
Yuichi Mihara (三原 雄一, Mihara Yūichi) is a japanese boxer and ranked 5th in the lightweight division and training in the Hyodo Gym.
Going to see Tsubaki's title defense, outside he saw a couple kissing and recognized it was Riku. When he saw Riku inside the arena, he complimented him for being able to seduce a woman, but Riku wondered who he was. Mihara then called for the reporters, telling them that this was Azami who would fight Kaede Hyodo. He introduced himself and asked them to interview him too, but they ended up only interviewing Riku. Mihara was surprised that Riku said he had no self-confidence and told him he had to say what they wanted to hear. During the fight he sat next to Riku as the seat was empty and then invited him to meet Tsubaki. At the back stage Tsubaki scolded him as he brought up pollen, which activated his allergies.
At the gym, Kaede told Mihara about his weakness that his pelvis and arm are off when he punches. Mihara commented that Tsubaki said the same thing, and then he was scolded by his friend telling him that then he needs to fix this. He went and gave Kaede and advice, to not underestimate the lower ranks as Rookie King can become quite bloody.