Thousands of people fled after a powerful earthquake rocked the north-east Japanese coast and triggered a metre-high tsunami in an area devastated by last year's Fukushima disaster.
Broadcasters urged residents to remember the 2011 catastrophe and move to higher ground when the initial 7.3 magnitude tremor struck the region.
Telephone systems were jammed by calls, complicating officials' efforts to evacuate exposed areas until a tsunami warning was lifted two hours later.
Meteorologists said the wave swept ashore just after 6pm on Friday in Ishinomaki, a city badly hit by the 2011 quake-generated tsunami that wrecked a large swathe of coast, killing thousands.
There were no immediate reports of any fatalities following the latest quake.
The NHK network reported 10 people were hurt, including a 36-year-old woman in Ibaraki prefecture who suffered injuries after a wardrobe fell on her.
None of the injuries were thought to be serious, the broadcaster said.
Several smaller tsunamis were also recorded, including a 40-centimetre wave at Soma, a city just outside the evacuation zone declared around the Fukushima nuclear plant after meltdowns there last year.
Operator Tokyo Electric Power (TEPCO) told AFP there were no reports of any problems at the crippled plant.
Broadcaster NHK reported 5,000 people had fled in Miyagi prefecture, a region devastated in last year's disaster.
Officials in Minamisanriku, Miyagi prefecture, said they were doing their best to get people to safety but were running into difficulties.
"We are now calling on people to evacuate to higher ground," town official Ryuichi Omori told AFP shortly after the quake struck.
"It's already pitch dark here. Phones - both landlines and mobiles - are not going through now, which makes it difficult to see people's movement."
Last year's earthquake and the following tsunami, in March, killed nearly 20,000 people and triggered the world's worst nuclear crisis in 25 years. The Fukushima-Daiichi nuclear plant was destroyed, leaking radiation into the sea and air.
The new quake rocked buildings in Tokyo.
Ishinomaki, where the latest tidal wave rolled ashore, was at the centre of the devastation from the March 2011 disaster. All Miyagi prefecture trains halted operations and Sendai airport, which was flooded by the tsunami last year, closed its runway.
Narita airport outside Tokyo was back in action after a brief closure for safety checks.
Prime Minister Yoshihiko Noda cancelled campaigning in Tokyo ahead of a December 16 election and was on his way back to his office, but there was no immediate plan to hold a special cabinet meeting.
Public spending on quake-proofing buildings is a big election issue.
Transport systems in the region were briefly interrupted, but normal service was resumed a short time later.