Japan's southernmost main island of Kyushu was bracing for torrential rain and high winds on Monday, as the third typhoon in three weeks threatened the region.
Typhoon Songda has wreaked havoc in more southerly islands over the past two days, injuring at least 26 people in and near Okinawa, cutting electricity to about 50,000 households and forcing schools to close.
Songda, the most powerful typhoon to hit Okinawa in several years, stranded tourists in the popular holiday area as flights and ferries were cancelled.
At 7 pm (1000 GMT) the storm, with winds of up to 144 km (90 miles) per hour, was 280 km (175 miles) north-west of Naze city on the tiny island of Amami Oshima, north of Okinawa, and moving north at 10 km (6 miles) per hour, the Japan Meteorological Agency said.
Idemitsu Kosan Co, Japan's third-biggest oil refiner, said it had stopped shipping and loading at its Okinawa supply and storage facility because of the storm.
Songda, named after a river in Vietnam, is expected to pound parts of Kyushu and inch its way along Japan's west coast facing the Sea of Japan over the next three days, battering many areas damaged in the previous two typhoons.
Parts of south-western Japan can expect up to 500 mm (20 inches) of rain by Tuesday morning, the agency said.
South Korean authorities shut several southern ports on Monday afternoon because of the approaching typhoon, threatening backlogs of shipments into the fourth-biggest oil-importing country.
An official at the maritime affairs ministry said Pusan Cheju, Yosu and other southern ports had been shut after the warning of Songda's approach was issued at 0600 GMT. Pusan, at the peninsula's south-eastern tip, is the country's largest port.
"Ports between Mokpo, on the western part of the south coast, and Pusan have been closed since 3:00 pm (0600 GMT) until the typhoon warning is lifted," said Lee Hyun-seog, an official at the ministry's anti-disaster department.
The latest data indicated the centre of Typhoon Songda might make landfall on Tuesday near Shimonoseki, at the south-western tip of the Japanese main island of Honshu, the agency said.
Six typhoons have already hit Japan's main islands this year, twice the normal average.
Songda follows close behind Typhoon Chaba, which killed at least seven people last week, and Megi, which killed 13 in Japan and South Korea in August.