Mitsuko Tottori's appointment as Japan Airlines' next president makes her something of a rarity in Japan — a female head of a well-known company.

While Japanese firms have rapidly lifted the number of female board members in recent years, most are outside directors. Change from within is slower in coming.

Under pressure from the government, the Tokyo Stock Exchange (TSE) and foreign investors, firms have been scrambling to improve diversity, including on their boards, bringing in external directors who are often lawyers, academics and accountants.