The blaze broke out in the Bunkyo Ward residence Monday afternoon. More than 20 fire engines were deployed in response.
About 800 square meters of the site was burned down, including all of a two-story house and part of a one-story residence.
Police say the former prime minister's daughter Tanaka Makiko, who once served as foreign minister, and her husband and former defense minister Tanaka Naoki were on the premises along with two other people.
Comment:
None of them was injured.
Makiko reportedly said that she had burned incense sticks in the two-story house earlier in the day.
Police will investigate the cause of the fire.
Comment: Whilst accident is always a possibility, considering the relatively high profile nature of the occupants and owner, together with other events in Japan of late, it seems more likely that this was arson, and maybe a warning: