How common are such transfers in Japan?
A government survey said, "men who have a family but live alone and aren't divorced" in all Japanese family numbers is 2.5%*.
However, I disagree somewhat. As a big company (means it has many offices all over Japan) worker, my feeling is about 10 to 20% ("tanshin funin" (Japanese word for job transfer away from their family) of men among my all headquarters offices) or 5% (among my all regional offices). I have never met any businesswomen who have experienced tanshin-funin in my company except only one case.
Photo by Pawel Janiak on Unsplash
Why do Japanese big companies mandate such transfer of their workers?
Actually, companies never command their workers to live apart from their families for work. Companies prepare their new home and pay for the move. However, workers choose to live alone after discussing with their families. They value "not changing the children's school and friends" or "not changing the environment for raising kids. (frequently means their wife's mother living near their home) than "living family together" .
Anyway, such hard choices in families never appear if big companies never mandate such transfers. Why? Many companies including my company say the reason why is "the result of thinking what is the best position for workers to suit their abilities". I have never heard a clear reason from companies. In my opinion, a part of company's reason is true but the cost (workers' and their family members' quality of life getting worse) is so high, therefore the tanshin-funin system is very unreasonable.
How about me? In my company's custom (with no documented rules), if you become a manager, the first position will be far from your current area of residence. If you have family, you will experience tanshin-funin. Therefore I declined to receive the examination for a promotion.
One of some good results
This month (July of 2020), a famous Japanese confectionary maker has decided to abolish tanshin-funin because the telework environment has become popular. Fujitsu has also decided to switch from tanshin-funin to telework. The Coronavirus is causing huge problems all over the world but leaving some good results. Reduction of tanshin-funin must be one.
*The numbers of tanshin-funin(in Japanese)