In Japan, women make 77.5 cents for every dollar men earn when comparing median hourly pay for full-time work. Among advanced economies, Japan ranks second from last against an average of 87.2 cents, meaning in practice that Japanese women must work over a quarter of a year more than their male colleagues to earn the same pay. The gender pay gap lies at the heart of numerous societal concerns in Japan, ranging from the high poverty rate among elderly women to the low birth rate among the younger generation. As such, the gender pay gap helps crystallise the abstract enormity of gender inequality . It is a helpful gauge on which to focus our attention when a nation attempts to move the needle on gender equality. Several recent moves have brought this into sharp focus. The Tokyo Stock Exchange implemented its biggest revamp in more than 60 years in April. A long-awaited restructuring has seen its market segments simplified into three new sections, from the original five. The reform aims to consolidate the segments into distinct, easy-to-understand categories and in doing so lift governance and transparency standards for listed companies. This has been hailed as a once-in-a-generation shift, with market reform promoting corporate reform. Will it move the needle? Under Prime Minister Fumio Kishida , Tokyo is emphasising the “social” part of environmental, social and governance (ESG) management, vowing to encourage private-sector investment into human capital. Disclosure of non-financial metrics including the gender pay gap could become mandatory. It is this idea that presents a catalyst for Japan to advance on gender equality and should be introduced without further delay. It is the micro-level figures, which are more transparent and comparable from company to company, that can trigger immediate reactions. Experts see the causes of the gender pay gap as either “horizontal” or “vertical” uneven distributions along the gender axis. A horizontally uneven distribution results from gender bias in occupation choices. Higher-paying occupations such as medical doctors and engineers are heavily skewed towards men, while lower-paying occupations such as nurses and kindergarten teachers are dominated by women. In contrast, a vertically uneven distribution links to gender-based variations in staff seniority within an organisation. The more senior the ranks, the more the ratio of men increases. Japan suffers from both horizontal and vertical causes. Gender equality at work: how do Hong Kong, Singapore and others compare? Mandating employer disclosure of gender pay gap data would address vertical separation. According to analysis by the Gender Equality Bureau Cabinet Office, the gender distribution skew within seniority levels most heavily explains the gender pay gap in Japan. Japanese leadership positions are predominantly held by men – in 2021, only 6.1 per cent of public company board members were women. Mari Kogiso, founder and co-CEO of impact investing firm Impact Japan, points out that only by mandating regular disclosure of gender pay gap data can we anticipate an improvement. As of 2021, only 18 of the 31 Organisation for Economic Cooperation and Development member countries mandated disclosure. Those with a penalty for non-compliance show stronger evidence of improvement over a relatively short time after the disclosure mandate. Disclosure is not the complete answer, of course. Employers must also ensure women stand an equal chance of promotion. Japan must ensure the disproportionate number of women at the bottom of the pay scale are given a chance to learn new skills. We must use the emergence of flexible work as a catalyst. With remote work normalised during the pandemic, there is less emphasis on face time. This creates space for a results-based meritocracy which should reward those who perform well and increase women’s pay, even if they work fewer hours. Finally, women must harness the anger created by the in-your-face gender pay gap figures at their workplace to kick-start a change in attitude. It is second nature for Japanese women to keep their heads down and work hard, often in support roles to men. However, women need to become their own agents to negotiate promotions, demand reskilling and push for fair wages. The gender pay gap acts as a wake-up call. Even though much airtime has been given to criticising gender inequality at work, change has been slow: two years ago, the government quietly withdrew its goal to have women occupy more than 30 per cent of managerial positions by 2020. Gender equality policies in Japan need teeth – let’s start with disclosure of the gender pay gap. Nobuko Kobayashi is a partner and Asia-Pacific strategy execution leader at EY. The views reflected in this article are solely those of the author