The quake struck at 7:20 a.m. Saturday (2220 GMT Friday) just off the coast of Hokkaido, the northernmost of Japan's four main islands, the agency said.
The temblor rattled areas along Hokkaido's southern coastline as well as the northern reaches of Japan's main island of Honshu, but there were no immediate reports of damages or injuries.
Japan is one of the world's most earthquake-prone countries because it sits atop four tectonic plates.
Brenton Tarrant, the shooter from New Zealand's Christchurch, was not a lone wolf. The West has missed out an important point - the formation of organised Christian extremism
Those who convientenly blame Muslims and Islam for "extremism" and "terrorism" should rethink and read the living history for truth, honesty and justice
The Moroccan occupation remains the last case of decolonization in Africa. The Moroccan military invaded in 1975 despite a clear ruling issued by the ICJ.