Monday marks six months since the massive New year's day earthquake struck the Noto Peninsula along the Sea of Japan.
The quake left local mobile phone networks paralyzed in many areas. Nearly 60 percent of base station cables were damaged far more seriously than in previous disasters.
The tremor left more than 3,300 people isolated in up to 24 areas in the central prefecture of Ishikawa.
Yamashita Tomotaka, a community leader in a mountainous area of Wajima City, said mudslides blocked all three access roads.
He said all mobile phones and fixed-line phones were useless immediately after the jolt.
Residents were unable to call for help from city authorities or anyone else.
"It was even impossible to call an ambulance. It's truly tough to be left without any means of communication," Yamashita said.
Six days after the quake, residents were finally able to make contact with the outside world. Ten days after the jolt, Self Defense Forces helicopters arrived to airlift about 30 residents to safer locations.
People in other parts of the prefecture had similar troubles. A communications ministry survey found that 57 percent of cables were rendered useless by mudslides or other problems. It was a situation far worse than in the 2011 quake and tsunami in northeastern Japan.
Toyo University Professor Nakamura Isao said: "Here in the mountainous terrain of the Noto Peninsula, the quake triggered landslides that caused extensive damage to transmission lines. People's daily lives and administrative functions rely on telecommunications. And that's becoming more important than ever. I think it's necessary to maintain some form of continuous and dependable information channels."
A US satellite communication network called Starlink was installed at evacuation shelters and elsewhere until mobile phone and internet connections were restored. More than 600 devices, including reception antennas, were loaned out by the US firm and Japan's government.
The Starlink system was installed at an evacuation center in Suzu City. Iseki Juichi is a resident who did radio service work. He says some people didn't know how to make full use of the new system.
A medical support group visiting the shelter was unable to use an app to connect to the system, so Iseki helped them sort it out. He says that in other shelters antennas were set up in areas with poor radio wave reception.
The communications ministry is planning ways to improve emergency power sources at major base stations. It wants to make satellite connections available between the stations in the event of severed power cables.
The ministry is also setting up a system in which locals can have secure communications when disasters strike.