https://www.nhk.or.jp/kishou-saigai/tsunami/

A 1M tsunami is about to hit Japan's East Coast in about half an hour.

Stay away from the beach!

EDIT: Map from JMA

EDIT 2: English live coverage from NHK World

EDIT 3: NHK is reiterating that a tsunami may hit the coast repeatedly. It's not necessarily over yet. Stay alert.