Great earthquakes had migrated from south to north along the trenches of the Japan Arc until 1611. But the direction of migration reversed, flowing in a north-south direction beginning in the year 1677. The influence of the change in the migrating direction reached as far as Northeast China and included the Korean peninsula. Then, seismic activity changed suddenly in these two regions and a long aseismic period began. It continued for about 150-250 years. A seismic activity started again in the Japan Arc with the 1843 earthquake in the Hokkaido region. The seismic activity in the Korean peninsula began again with an earthquake in 1906, and the last epoch of seismic activity in Northeast China began in 1970. The velocity of the migration of activity from the Japan Arc to Northeast China is estimated to be about 20-30km/y. Great earthquakes along the trenches have repeatedly migrated from north to south. Recently, seismic activity has again turned northward, where two great earthquakes occurred in 1952 and 1968. If this order of migration were to hold, the next earthquake would occur in the Kanto region around the year 2000.