REUTERS
The Japan Meteorological Agency (JMA) said the system, which is already producing winds up to 150 mph, may develop into an "extremely intense" storm by Tuesday as it moves north.
It is expected to be as strong as Typhoon Haiyan, which killed thousands in the Philippines last year, but it is clear that Japan will have to batten down the hatches.
Around two to four typhoons a year make landfall in Japan but they are unusual in July. This one is not expected to threaten any nuclear power plants.