Japan is prone to natural disasters, yet many Japanese don’t remember their loved one’s cell number, because these days they can reach them anytime using a cell phone app. According to a survey, 98% of people want to memorize the cell number of their closest family member or loved one in case disaster strikes. Yet even among people who have personally experienced a disaster, only 1 in 2 remember the number. So we decided to get people to engage in a new form of disaster preparedness: memorizing the cell number of a family member or loved one so they can contact them in an emergency, even if their cell phone is lost or broken.

NTT Docomo has a wide range of disaster response measures in place. But it wondered how to deliver peace of mind when people couldn’t reach each other in an emergency, not just when they could. It therefore developed a method of memorizing a family member’s or loved one’s cell number using a mnemonic mechanism. This is a new form of disaster preparedness: in an emergency, it means you can immediately contact that person, even if your cell phone is lost or broken. The service was intended to target people of all ages, from teens to sexagenarians. So we designed an interface that anyone could easily use on their cell phone. Once you memorized your loved one’s cell number, the system let you send a message telling them you’d done so, thus spreading the word. The service has brought many loved ones closer together.

In a survey, we asked men and women in their 20s to 50s who had personally experienced a disaster whether they’d be interested in trying a service that helped one memorize cell numbers. Some 80% of them said “Yes, I would” or “I would if I get the chance.” These results demonstrate that most people who have been in a disaster want an easy way to remember a loved one’s cell number. They show that remembering a cell number is valuable in a disaster — and how much people care about their loved ones.

We therefore designed a service called “11 Digits Just in Case, with Love.” This enables anyone to easily memorize a loved one’s cell number at any time, in just one minute, using a device everyone owns, a cell phone. It also lets them inform their loved one they’ve used the service.

The service was launched in March, the month when the massive 2011 earthquake and tsunami struck. It’s a time of year when disaster awareness increases in Japan, and special features on disaster preparedness appear in various media. Rolling out the service at that point ensured that it was talked about and struck a chord as a new and easy way to prepare for a disaster.

The service was rolled out on the corporate website in March 2022 in readiness for a disaster that could strike at any moment. “11 Digits Just in Case, with Love” is an online service that can be used by anyone anywhere in Japan who owns a cell phone, regardless of their carrier.

The site recorded a maximum of 3,100 page views a day. Despite being announced on owned media, the service was extensively covered by many different media, including TV news shows, newspapers, radio, and online news sites. It earned more than 32.43 million impressions. “11 Digits Just in Case, with Love” fostered communication by getting consumers thinking about loved ones. More and more of them memorized a loved one’s cell number. We created a completely new form of disaster preparedness that struck a chord with people by giving them a few tender moments to think about their special someone. We turned preparing for a disaster into a reminder of how dear they and their loved ones were to each other.