Kohyama shapes his asymmetrical forms using piano wire, creating distinctive rough surfaces. The clay with its feldspar nuggets creates a tactile quality rarely seen in contemporary work. No glaze is used, but the wood ash and placement in the kiln produces an extraordinary range of colors and shading on the surface.

The artist's masterful ceramics are inspired by ancient Shigaraki, Jomon and Yayoi from Japan. He played an important role in reviving the use of the traditional Japanese anagama wood-fired oven. He was the first potter in the region to build such a kiln since the Middle Ages. Using the distinctive Shigaraki clay and a wood-fired oven, he created modern, vigorous and new ceramic vessels and sculptures, but of timeless beauty.