"We'll start our sotsukon [graduation from marriage] life. We'll live in different places in the north and south and visit each other," wrote Shojiro Shindo, 71, of Iwamizawa, Hokkaido, in this year's New Year's greeting cards.
"Sotsukon" has gained popularity among elderly couples as a way to remain married but live apart after they retire or when their grown-up children leave home.
Shindo and his wife, Kimiko, 69, raised three daughters. The couple have been married for 46 years, and were both physical education teachers at high school and taught at university.
After retiring, Kimiko told her husband she wanted to live a self-sufficient life. She rented a vacant house on Amami-Oshima island in Kagoshima Prefecture and started living as a farmer there in July last year. Her living expenses come to ¥40,000 (S$485) to ¥50,000 each month.
"My neighbours give me vegetables and fish," she said. "I also attend gatherings with local people. I feel very fulfilled every day."
Shindo continues to live in their home in Hokkaido. "I was born and raised here," he said. "I like Hokkaido."
He serves as a vice chairman of the local residents association, plays with his grandchildren, who live nearby, and goes skiing. He has no time to be bored.
The couple frequently phone and e-mail each other. They also visit each other using one-way budget airline tickets priced at about ¥15,000.
"Sotsukon" combines the words "sotsugyo" (graduation) and "kekkon" (marriage). This type of lifestyle for married couples was first suggested by writer Yumiko Sugiyama in her book "Sotsukon no Susume" in 2004.
The phrase became widely known in 2013 when entertainer Akira Shimizu announced he would "graduate from marriage."
Sotsukon appeals to many women today, according to a survey conducted in 2014 by the Interstation architectural design firm in Tokyo, which suggests ideal housing for elderly people.
In the survey covering 200 married women in their 30s to 60s, a total of 57 per cent of the respondents said they wanted to live this kind of life in the future. Many said they wanted to live separately when their husbands retire.
Among the benefits of sotsukon are that couples can live separately while maintaining their social status as a married couple, and they can once again see each other's good points, according to marriage counselor Atsuko Okano.
Reasons for deciding to live apart vary. One 48-year-old woman said in the survey: "I want to have time to myself. It's annoying to have to tell my husband every time I want to do something." A 46-year-old woman said she wanted to be released from doing household chores.
"In a way, sotsukon helps prevent divorce," Okano said. "The ideal sotsukon is based on a constructive agreement between a husband and wife, but I'm afraid there are not many cases like this."
Okano has suggested a "small sotsukon," such as temporarily returning to a parent's home or travelling with friends, to women who visit her for advice about divorce or living apart from their husbands.
"Sotsukon sounds good and can be easily understood by other people," she said. "Many elderly women who are worried about their relationships with their husbands want to choose the lifestyle."
This could be taken to mean that sotsukon is a good course of action for women who've had to cope with their husbands' thoughtless behaviour for a long time. They can live their own lives without seeing their marriages collapse.
On the other hand, husbands want to use sotsukon to pursue their dreams, such as living in the mountains with pet dogs and farming in the countryside. As a result, in some cases, wives are forced against their will to live separately from their husbands.
The husband of a woman in her 60s bought a house in the Tohoku region after he retired. He now enjoys climbing mountains and farming. The woman opted to live alone in their house in Tokyo, as her daughter and friends all live in Tokyo.
While happy to be released from the duties of being a full-time housewife, she said, "Honestly, I wanted to live together [with my husband]."
To prevent sotsukon from developing into a loveless separate life or relationship that forces only a husband or a wife to endure a situation either one does not especially want, it is crucial to express appreciation, such as "Thank you for allowing me to live alone," and show consideration, according to Okano.
Yasuko Matoba, an executive researcher of Dai-ichi Life Research Institute Inc., says married couples today are becoming less committed to the division of work based on gender.
"When I asked people in their 70s and 80s about the secret of a happy marriage, many said 'perseverance.' These people belong to a generation who believe married couples should live together until death takes one of them. They don't approve of divorce or living separately," Matoba said.
"However, as the number of couples who both work increases, marriage lifestyles have become more diversified," Matoba said. "More and more people are departing from the conventional gender-based division of work, such as wives taking care of their husbands. This trend probably has led to increasing interest in sotsukon."
Even if married couples live separately, they can communicate easily via information technology and transportation systems. Marriages are becoming longer because society is aging. Therefore, perseverance does not always work, according to Matoba.
"In the future, more and more couples may live new types of sotsukon lives in which they continue living together and maintain mutual trust without restricting or depending too much on each other," Matoba said.