A 30-centimeter (12-inch) high tsunami reached the shore of the northern Japan city of Ofunato, Iwate prefecture, at 7:26 am (22:26 GMT Monday), a municipal official said. Smaller seismic waves were also observed in the prefecture.
The coastal village of Tanohata in Iwate ordered some 400 households to evacuate, public broadcaster NHK said.
There was no immediate reports of major damage.
The quake, which occurred at 6:39 am (2139 GMT), was centred very shallow off the northern Japan coast.