An old, disconnected black telephone stands in a telephone booth in the town of Otsuchi – about 20 minutes' drive from Kamaishi, Iwate Prefecture.

Since the Great East Japan Earthquake and the accompanying tsunami of 2011, the phone has been visited by at least 25,000 people, the grief-stricken who have come to convey their feelings to departed loved ones "through the wind".

The phone was set up by 72-year-old garden designer Itaru Sasaki in his garden, on a small hill with a commanding view of the calm sea in the Namiita area of Otsuchi. Calling it "Kaze no Denwa" (the phone of the wind or wind phone), Sasaki originally set up the phone after the death of his cousin.

The garden is open to all, and there is a notebook placed by the phone, the fourth such notebook to be used. Many have left messages for their loved ones.

Sasaki began work on the booth in November 2010, and completed it shortly after the disaster. Newspapers and other media reported on it, and many people who had suddenly lost a loved one began to visit.

Located on the Sanriku coast, Otsuchi was devastated by the March 2011 tsunami. In the town, 1285 people died or went missing, about 10 per cent of its population. Forty people, including the mayor, died in the former town office.

In late 2013, Sasaki found this message: "Come home soon. From your father, mother and grandparents."

 He eventually met the family who had written it and learned the story. They were looking for their son, who had gone missing in the disaster. After graduating from university, their son had started working at an IT firm and was visiting Otsuchi on a business trip when the disaster struck.

Reflecting on memories

The mother revealed her feelings to Sasaki, saying: "I have no idea what I've been doing since that moment. Time has stood still for me since that day."

Sasaki said messages in the notebooks have changed as time has passed since the disaster. People have started to accept the deaths of their loved ones, writing things such as "Please watch over us from heaven."

In addition to people lost to the earthquake and tsunami, families who lost a loved one in an accident or from suicide are also coming to the garden to reflect on their memories of that person.

One morning in early July, I visited the garden to find a photo in the telephone booth in which an apparently foreign man is smiling at someone. I felt like  a "caller" had just had a conversation with him.

The phone has become known even overseas, and there are messages in the notebooks recalling people lost abroad.

On Tuesday, Sasaki's book titled Kaze no Denwa – Daishinsai Kara Rokunen, Kaze no Denwa wo Tooshite Mieru Koto (The phone of the wind – what I have seen via the phone in the six years since the earthquake) was published in Japan by Kazama Shobo.

"The telephone is not connected, but people feel like their lost loved ones are there listening on the other end of the line," Sasaki said. "I want people to resume their lives as soon as possible by expressing their feelings."