The aircraft went down in Gunma Prefecture on Wednesday at around 2:30 PM.
Police and firefighters who rushed to the scene found the crashed helicopter in flames on a bridge.
Video taken by NHK shows charred wreckage partly covered by a blue sheet, and pieces of the aircraft scattered in the river beneath the bridge.
The crash site is a mountainous area dotted with houses. Local officials say the site is about 500 meters from the village office. A witness said the helicopter appeared to be flying very low and then it crashed.
The aircraft was operated by Toho Air Service.
It had been chartered by a firm affiliated with Tokyo Electric Power Company to transport materials to repair a power generating facility in Yamanashi Prefecture.
It reportedly left a heliport near the plant about 30 minutes before the crash.
A helicopter carrying 4 people has crashed near Tokyo, killing everyone on board. (NHK)
A 65-year-old man is believed to have killed himself with a hunting rifle Wednesday after first shooting his pet dog dead at his home in southwestern Japan, in a case in which police initially feared he had holed himself up and was a potential danger to other people. (Japan Today)
Some Japanese government and ruling camp officials have proposed a tobacco tax increase of 3 yen per cigarette over several years beginning in October 2018, informed sources said Wednesday. (Jiji)
The government will seek to lower the age of adulthood from 20 to 18 during the ordinary Diet session to be convened in January. (Japan Times)
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Eighty local governments in Japan are considering or making preparations for the establishment of pubic night junior high schools to be attended by people who were unable to finish compulsory education for various reasons and foreigners, the education ministry has said. (Jiji)
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