Only one female executive made it to the top-earner list of Japan’s Nikkei 225 companies last year. She is an American who lives in New York.

Nicole Seligman, president of Sony of America and Sony Entertainment, is the only female among 185 executives who earned 100 million yen ($978,000) or more, according to data compiled by Bloomberg.

Kazuo Kashio, president of Casio Computer earned the most, with 1.2 billion yen in compensation, and Canon chairman Fujio Mitarai was second with 1.1 billion yen, according to the data that looked at the pay of the top executives at Japan’s 225 biggest companies in the last reporting period.

The absence of Japanese women in the top echelons of business reflects challenges the country faces in boosting the number of female leaders as Prime Minister Shinzo Abe pledges to fill 30 per cent of management positions with women by 2020. It is also a result of lower female labor participation in a nation known for long working hours, a shortage of childcare facilities and a culture in which women are often relegated to serving tea in workplaces.

“It’s becoming clear that Japan’s economic growth won’t be sustainable if we don’t utilise women in the workforce,” said Akira Kawaguchi, a professor at Doshisha University in Kyoto. “For corporations, they won’t be able to hire the best talent if they only focus on men.”

Women on average accounted for 6.2 per cent of management positions, according to a survey of 11,017 Japanese companies by Teikoku Databank Ltd., Japan’s largest credit research company. About 52 per cent of companies surveyed don’t have any female managers, it said. Women fill 34 per cent of management positions in the UK and 44 per cent in the US, according to a Japanese government report.

Even as Japan’s female labor-force participation rate rose to a record 64 per cent as of June, it is still lower than the 82 per cent rate for men, according to the Ministry of Internal Affairs and Communications.

Japan’s gender wage gap is the second widest among Organisation for Economic Co-operation and Development countries, trailing only Korea, where it’s 37 per cent. The 27 per cent gap in Japan compares with 19 per cent in the US and 6.2 per cent in New Zealand, which has the lowest wage gap among OECD member countries.

Prime Minister Abe plans to bring more women into the workforce as part of his growth strategy for the world’s third- largest economy as the country’s population declines.

Some women opt out of a career with large corporations, said Kumi Sato, president and chief executive of Cosmo Public Relations Corp. and a winner of Harvard Business School Club of Japan’s “Business Stateswoman of the Year” in 2012. “For a long time, Japanese women didn’t want to pursue the let-me-join-the-big-corporations route; it’s really not a very attractive workplace,” said Sato, a mother of three. “You are at the mercy of a big corporate bureaucracy. You have to go out drinking with your boss and follow rigid rules.”

A lack of sufficient childcare support also has kept some women at home, said Sato. Only 38 per cent return to work after giving birth, according to the labor ministry. About one in three women who quit said the working environment doesn’t allow them to juggle both work and family, according to a survey by Nomura Research Institute. Sato, a former chairman of the American Chamber of Commerce in Japan, was part of a team that published a paper in June 2013 recommending the government loosen regulations to allow Japanese citizens to sponsor foreign domestic workers.

“Women have to carry a lot of the burden,” said Sato. “There are few support structures that give women a real option to continue to work.”

Men and women in Japan start off with the smallest wage gap. A female 20 to 24 years old at the beginning of her career makes about 86 per cent of a male colleague, according to the National Tax Agency. That percentage drops over time to about 50 per cent for women in their 40s and remains at that level throughout the rest of their careers, the data show. That compares with women in the U.S. earning 77 per cent of what their male counterparts make, according to the U.S. Census Bureau.

The wage gap between men and women in Japan is partly due to a hiring system adopted by large corporations that divides employees into career and non-career groups, Doshisha University’s Kawaguchi said. Those in the career group, or sogoshoku in Japanese, will advance and become managers, while the non-career group, or ippanshoku, will be in charge of assisting others, he said. Men accounted for 88 per cent of those hired for the career route, while women represented 86 per cent of non-career hiring in 2011, according to a report by the Ministry of Health, Labour and Welfare. “Large corporations already have different mindsets when they hire men and women,” said Kawaguchi. “Companies must choose both men and women with a mindset that both genders can become future managers.”

Bloomberg