There has been no tsunami alert issued.
There are plenty of headlines about re a 'Japan earthquake'. This is the one. Its not close to the main islands of Japan .
Depth reported 62km approximately
Map via USGS:
Large earthquake around Japanese islands - a LONG way from Tokyo
- M6.4 (approx) nearJapan's Ogasawara archipelago, which is around 1000km almost directly south of Tokyo