Report of the British Mission to Japan
Nagasaki
Reinforced concrete school with a timber roof, 500 yds from the centre of damage, which is to the right of the Photograph. The upper part of the long wall further from the explosion has been bent over, partly by a thrust through the roof from the other long wall and partly by wind suction This is a typical case of " mass distortion." See paragraphs 15 and 22.