Typhoon Hagibis is forecast to bring 60cm of rain and damaging winds to the Tokyo area and central Japan's Pacific coast this weekend, and the Government is warning people to stockpile and leave high-risk places before it's too dangerous.
Rugby World Cup matches and other events were cancelled for Saturday, and flights and train services halted.
In the town of Kiho, in Mie prefecture southwest of Tokyo, shops were boarded up, boats were anchored, and authorities checked coastal levees.
Residents in Tokyo were buying bottled water, cup noodles and other food.
"In order to protect your own life and your loved ones, please try to start evacuating early before it gets dark and the storm becomes powerful," Meteorological Agency forecast department chief Yasushi Kajihara told a news conference.
Kajihara said Typhoon Hagibis resembled a typhoon that hit the Tokyo region in 1958 with heavy rains and left a half-million houses flooded. More than 1200 people died in that storm.
Prime Minister Shinzo Abe's Cabinet is to hold a disaster management meeting later Friday.
"The government is doing the utmost to prepare for the approaching typhoon," disaster management minister Ryota Takeda told reporters, and urged people to prepare early.
Economy Minister Isshu Sugawara urged hospitals and other public facilities to check their backup power.
Hagibis, which means speed in Filipino, was advancing north-northwestward with winds of 180km/h gusting to 250km/h this afternoon, the weather agency said.
It's expected to weaken as it hugs the Pacific coast of Japan's main island tomorrow, making landfall south of Tokyo and passing out to sea by Sunday afternoon.
Up to 800 millimeters of rain was forecast south and west of Tokyo, while the capital region may see 600mm of rain from tomorrow morning to Sunday morning.
The storm is expected to disrupt sports and holiday events on the three-day weekend that includes Sports Day on Monday.
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Two Rugby World Cup matches — England versus France, and New Zealand versus Italy — that were to be played Saturday were cancelled.
Qualifying for Formula One auto racing in Suzuka was pushed to Sunday.
And the Defence Ministry cut a three-day annual navy review to just Monday.
All Nippon Airways grounded all domestic flights scheduled on Saturday at Tokyo's Haneda and Narita international airports, while Japan Airlines has cancelled all but early morning flights at Tokyo airports.
Central Japan Railway Co. said it will cancel all bullet train services between Tokyo and Osaka except for several early Saturday trains connecting Nagoya and Osaka in the west.
The typhoon is spreading fear especially in Chiba, near Tokyo, which was hit by Typhoon Faxai last month and where homes still have damage.
Chiba city distributed sandbags to shield against flooding and urged residents to make sure they have enough food, water and their phones are charged.