There was no immediate tsunami alert or warning from the Pacific Tsunami Warning Center.
The quake, which struck about 9:19 a.m. local time, was centered 220 miles south-southwest of Hachijojima Island and 395 miles south of Tokyo.
China's Xinhua News Agency said the quake measured 6.9 on the Richter scale and its tremor was felt in Tokyo. The China Earthquake Networks Center measured it at 6.7 magnitudes.
There were no immediate reports of damage or injuries, Xinhua said.