The Bombing of Tokyo by B-29 long-distance strategic bombers based on the Mariana Islands began on November 24, 1944. Since the US military were initially unsuccessful in their attempts at precision bombing of the target munitions factories, from February 25, 1945 they changed their tactics to area bombing, destroying urban areas indiscriminately using incendiary bombs. Minato City area suffered air strikes 19 times from November 24, 1944 through August 13 the following year, with a large part of the city area destroyed by fire during that time through large-scale indiscriminate bombing on March 10, May 24 and May 25-26, 1945.
The early-period fire defense system of the neighborhood self air defense groups crumbled to pieces in the face of the unimaginable scale of the incendiary bomb attacks.