Dai Koyamada (Japanese: 小山田大, born 23 August 1976) is a Japanese rock climber and known as one of the leading boulderers of his generation who established some of the first-ever boulder problems at 8C (V15). He has also established and repeated, some of the hardest sport climbs in the world.
Source: “Dai Koyamada”, English Wikipedia (CC BY-SA 4.0), excerpt