Human Shadow Etched in Stone (人影の石, hitokage no ishi)[2] is an exhibition at the Hiroshima Peace Memorial Museum.
This effect was called the flash burn effect by investigators after the war, who studied it closely as the angles of the burn, and the specific changes to the surfaces, could be used to precisely determine explosion parameters after the fact, like its exact altitude, height of burst, and size of fireball.
[3][4] The British mission to Hiroshima and Nagasaki noted in 1946 that the surfaces of asphalt roads "retained the 'shadows' of those who had walked there at the instant of the explosion," and judged them "objects of macabre interest and pilgrimage for visitors".
[5] The "human shadow" at the entrance of the Sumitomo Bank was approximately 260 metres (850 ft) from the hypocenter of the atomic bomb explosion at Hiroshima.
If the shadow is of a human being, it indicates that the person absorbed sufficient heat to significantly burn or alter the surface of the steps they were obscuring.
Rather than vaporized or reduced to ash, the person would have any of their clothing or skin exposed to very high temperatures, and likely have been extremely burned, as well as subjected to the blast and radiation effects.
[1][6] The current location of the Sumitomo Mitsui Banking Corporation, Hiroshima Branch is Kamiya-cho 1 Chome.
It was designed by Kenzō Takekoshi (竹腰健造) at the department of engineering of Sumitomo Group (now Nikken Sekkei), and was constructed by the Obayashi Corporation.
It was designed in a general Romanesque architectural style, and was characterized by a large arch with molding on its front facade.