Even before the April abolition of a requirement that at least half a fund's assets be in yen-denominated fixed-income instruments, with a maximum of 30% each in Japanese stocks and foreign investments and 20% in property (the 5-3-3-2 rule), pension funds had considerable freedom to invest abroad but not to award specialist mandates for that purpose. Since this permission was granted in 1995, the business in awarding such mandates - especially to foreign houses - has been brisk.

While the same year saw the introduction of the last moves in the step-by-step phase of deregulation, custom and lingering restriction meant that stewardship of the pension assets of all but a minority of sponsors was in the hands of trust banks or life insurance companies with whom they had shareholding or business connections. The return produced by these corporate cousins was frequently dire. Then came a culture shift.

It was propelled by: worsening demographics in an already rapidly aging society, as 1989's 10.2 births per 1,000 population fell to 9.5 in 1995; the Nikkei stock index lolling below 15,000 against 40,000 in early 1990; the collapse of Nissan Mutual Life and moves by Japan's trust banks and money management firms to bring in overseas partners - with the sector itself recognising the need for foreign expertise.

Moves to modernise Japanese funds management pre-date by a decade any notion of staging a Big Bang on 1 April 1998. After typical Tokyo fashion they made only glacial progress in the early years then gathered a momentum which is now unstoppable. Yet while the pension system is immensely rich, it remains richly complicated.