Source: en.wikipedia.org Iconographical evolution of the Greek Herakles into the Japanese Shukongoshin.
Kongorikishi are an interesting case of the possible transmission of the image of the Greek hero Heracles to East Asia along the Silk Road. Heracles was used in Greco-Buddhist art to represent Vajrapani, the protector of the Buddha, and his representation was then used in China and Japan to depict the protector gods of Buddhist temples. This transmission is part of the wider Greco-Buddhist syncretic phenomenon, where Buddhism interacted with the Hellenistic culture of Central Asia from the 4th century BC to the 4th century AD.—-Wikipedia.