A strong earthquake registering magnitude 6.1 has shaken northern Japan, reports say.
But they said there was no danger of a tsunami.
Japan's Meteorological Agency said the quake struck off the southern coast of the country's northern main island of Hokkaido.
There are no immediate reports of damage or injuries.
The quake hit about 450 miles (750 kms) northeast of Tokyo.
The agency did not issue a tsunami warning.
The region lies on the Ring of Fire – an arc of earthquake and volcanic zones that stretches around the Pacific Rim. About 90% of the world’s quakes occur in the region.
Thousands of quakes have shaken Japan since the magnitude 9.0 earthquake and tsunami devastated the north-east coast in March. About 20,000 people died and damage at a Fukushima nuclear plant caused meltdowns and radiation leaks.
A second, magnitude 6.0 earthquake struck just off the coast near the nuclear power plant damaged by the March 11 earthquake and tsunami.
The two shakings are believed unrelated and did not affect the crippled Fukushima Dai-ichi plant or other nuclear plants in the region.
No apparent damage or tsunami was caused.