How may people did instantly die in Hiroshima?

It is not known how many people died instantly after the atomic bombings in Hiroshima.

Various Japanese and U.S. organizations conducted surveys after the bombing, but even today exactly how many people died as a result of the bombing is not known.

The reasons why it was difficult to ascertain the number of deaths caused by the atomic bombing in Hiroshima are as follows.

• Documents showing the population situation in Hiroshima right before the bombing were all destroyed by the atomic bomb.
• The population was in a state of flux, as many people left Hiroshima City for evacuation or, conversely, came to Hiroshima City for evacuation.
• Information on military personnel is unknown.

Regarding the number of deaths, it is estimated that approximately 140,000 (±10,000) people had died by the end of December 1945.