From April, companies with at least 1,000 employees have also been required to disclose what percentage of their employees take paternity leaves. That has added to societal pressure on companies to let fathers take time off to care for children.

Japan’s paternity leave system, which allows up to 52 weeks of paid time off, is the second most generous among countries in the Organisation for Economic Co-operation and Development as of last year. In comparison, the US does not have any national statutory paid paternity leave, while the average among OECD nations is 10.4 days.

Still, few men had been actually using the system due to a mixture of societal and corporate pressure.

“Employees have started to feel the change in society and corporate attitudes and have begun to feel that it’s OK to take paternity leave,” said Akiko Matsumoto, an assistant manager at Hitachi’s diversity and inclusion division.

Last year, Hitachi began offering seminars to expecting employees that outline available childcare and other related systems, and introduced tools that can calculate workers’ likely net incomes during parental leaves.

Moves to improve paternity leave take-up rates have made some progress among other Japanese firms. Sumitomo Mitsui Banking recently said it will double the amount of company-backed leave available to male employees to 20 days, until their child turns two.

“There was also a sense within the management that reaching a take-up rate of 100 per cent when it’s only a one-day leave is pointless,” said Chisa Kobuchi, a diversity and inclusion manager at the company.

Some firms are taking a further step in their approach. From August, Sekisui House launched a new system that allows parents to take leaves when their children are unable to go to school, or have a serious illness. Workers can either shorten their working hours or days, or take full leaves of up to two years.

“We were able to take this next step as we already had a culture where people can take time off through our support for parental leaves,” said Miwa Yamada, an executive officer and senior manager of Sekisui’s diversity and inclusion department.

Partly through government efforts to support women, the labour participation rate rose to 74.3 per cent last year among working-age women. That is 16 percentage points higher than when the childcare leave law was enacted in 1992, boosting the country’s labour market.

In Japan’s push for women bosses, equality is a secondary concern

But while more women work, they still shoulder the bulk of housework and childcare in the country. The amount of time Japanese women spend doing housework and childcare is more than five fold the time spent by men, according to OECD data. That is far above the 1.9 times average, and underscores how far the country remains to a more balanced division of labour.

Shungo Koreeda, a researcher at Daiwa Institute of Research, said a culture of long work hours at Japanese companies also needs to be revised. Without a change in the environment that allows men to more effectively be part of childcare even after their leaves are over, meaningful change may be difficult to come by.

Among couples with one child where the husband does not help with housework and childcare at all on his days off, only a third have a second child, according to a health ministry report published last year. That ratio goes up to more than 80 per cent when husbands spend more than six hours on housework and childcare.

Those figures suggest that resolving Japan’s lack of gender balance in work and care provision may hold the key to solving the country’s population crisis.