A quake with a preliminary magnitude of 5.0 quake shook Tokyo and its vicinity Saturday morning, the Meteorological Agency said.
The quake struck at 6:38 a.m. (2138 GMT Friday) and was centered off the coast of Chiba, the agency said in a statement. Chiba is 33 kilometers (21 miles) east of Tokyo.
There were no danger of tsunami, it said.
There were no immediate reports of injuries or damage from the quake.