Little is known about Tokuitsu's early life, but records state that he studied Hossō doctrine at an early age at Kōfuku-ji, then later Tōdai-ji.
Kōben sculpted notable statues of Tentōki and Ryūtōki, each considered a National Treasure of Japan, carrying lanterns as offering to the Historical Buddha at Kōfuku-ji in Nara.