The blue sky. The sky was clear that morning. Alert and air defense alarms repeated since the previous night, and a warning alarm was issued at 7:10, but contrary to the pressing situation, the weather was clear. Soon afterwards the alarm was lifted. After the lift of alarm was confirmed, Hirayama went to the Army Weapons Supply Plant. At that time, Hirayama was only a junior high school student in a private monastery school. His job in the weapons supply factory was to organize and carry the wood used for ammunition boxes. After 8:00 a.m., it was about 8:12 or 13 a.m. when Hirayama walked to the timber yard. Five or six students entered the hut and began to change their clothes and prepare for work. Hirayama went out of the cottage and looked at the clear sky as if he had something in mind. At that time, Boeing B-29 Superfortress, leaving behind a row of aircraft clouds, suddenly flew over the sky. Without any warning or alarm, parachutes appeared in the sky.