The damage from an overnight earthquake in a mountainous area of central Japan that hosted the 1998 winter Olympics proved more extensive than initially thought.
A daylight assessment on Sunday found at least 50 homes destroyed in two villages, and 41 people injured across the region, including seven seriously.
The magnitude-6.7 earthquake struck shortly after 10pm on Saturday west of Nagano city at a depth of three miles, the Japan Meteorological Agency said.
The agency revised the magnitude and depth from initial estimates. The US Geological Survey recorded a magnitude of 6.2. Since the quake occurred inland, there was no possibility of a tsunami.
Ryo Nishino, a restaurant owner in Hakuba, a ski resort village west of Nagano, told Japanese broadcaster NHK that he had "never experienced a quake that shook so hard. The sideways shaking was enormous". He added he was in the restaurant's wine cellar when the quake struck, and that nothing broke there.
Japan's Nuclear Regulation Authority said no abnormalities were reported at three nuclear power plants in the affected areas.
All of Japan's nuclear plants are offline following a magnitude-9.0 earthquake and massive tsunami in 2011 that sent three reactors at the Fukushima Dai-ichi plant into meltdown. Fukushima is about 155 miles north-east of where Saturday's earthquake occurred.
The hardest-hit area appeared to be Hakuba, which hosted events in the 1998 winter games. At least 43 homes were destroyed there, and 17 people injured, national and local disaster agencies said. Another seven homes were lost in Otari, a nearby village to the north. Non-residential buildings were also destroyed, with officials assessing the extent.
Japanese television footage showed buildings in various states of collapse, some flattened and others leaning to one side, and deep cracks in the roads. A landslide spilled onto a rail track, forcing services to stop. Roughly 200 people from Hakuba and Otari had evacuated to shelters.
Shigeharu Fujimori, a Nagano prefecture disaster management official, said it was fortunate there have not been any deaths reported despite the extensive damage.
More than 20 people trapped under collapsed houses were rescued, the National Police Agency told Japan's Kyodo news agency. Japanese television showed police going house-to-house Sunday morning, calling out to make sure that inhabitants were accounted for.
"The hardest-hit area was in the mountains and sparsely populated, where neighbors have a close relationship and help each other," Mr Fujimori said. "So I don't think anyone has been forgotten or left isolated."
Shinkansen bullet train service in the region was restored after a short interruption. Chubu Electric Power said 200 homes remained without power on Sunday.
The quake has been followed by more than 60 aftershocks, and Meteorological Agency official Yohei Hasegawa urged residents to watch out for landslides.
The area was struck by a magnitude-6.7 earthquake the day after the huge March 2011 quake.