A magnitude 5.8 earthquake has struck off the eastern coast of Hokkaido, according to the US Geological Survey.
The epicentre of the quake was 59km below the surface, the USGS said, in the sea off the coastal city of Nemuro on the far eastern tip of the northern island of Hokkaido.
Neither the USGS-linked Pacific Tsunami Warning Center nor the Japanese Meteorological Agency issued a tsunami warning after the quake which struck early on Sunday morning local time.