By Chris Hogg
BBC News, Tokyo
Japan expects a significant rise in the number of divorces from April, particularly among older people, because of a change in the pension rules coming into effect.
Hobbies can sometimes be an escape
The new system will for the first time allow women to claim up to half of their husband's pension if they end their marriage.
Experts say the fact that millions of baby boomers are due to give up work this year, forcing husbands and wives to spend a lot more time together than they ever have before, is likely to put extra strain on marriage too.
In a Tokyo dance studio, a group of Japanese women are practising the Flamenco.
For some of them this is a hobby. For others it is an escape.
Traditionally many Japanese women have had to take on all the responsibility for raising their family while their husbands work long hours and drink long into the night with colleagues.
Practically speaking, many men have been absentee spouses. But now more than five million Japanese workers (about 5% of the workforce) are about to retire as the Baby Boom generation reaches 60.
For the first time in their lives the women at the Flamenco class face the prospect of spending all day every day with men who have done nothing but go out to work all their adult life.
"I am so used to not having my husband around the house I'm very worried about his retirement, to be honest," said 59-year-old Yoshiko Yamauchi.
"When the day comes, I want to continue with my hobbies and what I enjoy doing. I hope my husband will take up hobbies on his own when he retires."
"If we get too involved with each other it becomes too stressful for both of us," agrees Kinuko Ito, the oldest in the group.
"That's why we want to live our lives separately but freely until the end."
Waiting to divorce
For those wives who have had enough, or those who find that living with a newly retired "salaryman" with nothing to do is just too hard, divorce is not an easy option in Japan.
Shame is one reason. Financial hardship is another.
Socialising with work colleagues keeps many men away from home
"Kaoru" is single again after years of marriage. She used a specialist divorce adviser to help her through what was a long drawn out and difficult process.
"It took me three years to decide to do it," she says.
"The money was really important. How was I going to manage? I'd heard that divorced women end up really poor - working as a cleaner or a maid. Eventually I got over all the other reasons that had been stopping me, but how to support myself after the divorce was a really big issue."
For decades the number of marriages that fail in Japan was increasing. It peaked at around 290,000 in 2002. Then everything changed. The trend reversed. Last year it had fallen to fewer than 260,000.
Kaoru's adviser Hiromi Ikeuchi says it is obvious why.
"People are waiting. In Japan, 75% of all divorces are initiated by women. They're waiting because if they plan to get divorced anyway they want to wait so they get part of the pension.
"They've been waiting for three or four years, ever since the government announced it was changing the law."
It seems some husbands could be in for a shock.
Many of them do not think they are doing anything wrong. They behave as their fathers did, as their boss does, as their colleagues do.
However not all Japanese men are giving up on their marriage.
I met a group of self-confessed male chauvinists in a restaurant on a Saturday night who want to do better.
This is the Tokyo chapter of what might best be described as the "National Chauvinistic Husbands Association".
For them the battle of the sexes is over. "We do not win. We cannot win. We do not want to win," they chant.
Over beers and steaming hot-pot they swap tips on how to save their marriages.
The association's founder Shuichi Amano says the club has more than 1,200 members across Japan and it is getting bigger.
"The most important thing is to learn to be a good husband," he said. "Not a chauvinist who orders his wife to prepare the bath, the meal and the bed but one who does what he's told. We've reached the stage where we need to have a big heart so we can solve any problems at home."
Some of the men say what they have been taught has saved their marriage.
Tengen Tanaka, 59, who teaches in a cram school, says he is learning little by little how to treat his wife better.
Some men are trying to overcome the chauvinist stereotype
"Before, there was a long distance between my wife and I," he admits. "But now we are getting closer and closer. I listen to what she says to me. This network is very important and unique in Japan and in the rest of the world."
And 28-year-old Yohei Takayama, who has only been married six months, agrees. He has been making notes all the way through the meal.
"Before, I used to think housework was just for women," he says. "Now I have changed my mind. I realised we need to share the burden, or rather I need to do all the housework. That is the way of showing my true love to my wife."
It appears that he is not joking either.
For these men the pain of divorce may yet be avoided. Millions of others might not manage it.
The change to the pensions law has been well publicised here, reminding their wives, an unhappy marriage no longer has to be endured.