Ishiyama serves green tea and autumn chestnut biscuits. She has been telling me about her investment history since around 2000 - the time, not coincidentally, when the Bank of Japan first pushed interest rates down to within a hair's breadth of zero. Largely without the knowledge of her husband, Ishiyama began investing the couple's money, mainly in lots of around $50,000. And didn't stop. Each fund in which she entrusted their retirement nest egg - or toranoko, "tiger's cub", in Japanese - has a more elaborate name than the last. As she lists each one she invariably adds as a suffix the words nantoka nantoka - "something or other" or "thingamajig". It is not altogether reassuring.
"Now let's see, there was the Global Infrastructure Thingamajig Fund," she says. "And the Emerging Currency Something or Other Fund. And the Australian Fixed Term Whatever-You-Call-It Fund." Shy and anxious (she refused to be photgraphed), 66-year-old Ishiyama does not look like someone who has played a role - however modest - in the drama that has engulfed the global financial system. Yet she and many of her peers have done exactly that. Japan's housewives have acted as the guardians of the country's vast household savings built up since its rise to prosperity after the devastation of war. At more than Y1,500,000bn (some $16,800bn), these savings are considered the world's biggest pool of investable wealth. Most of it is stashed in ordinary Japanese bank accounts; a surprisingly large amount is kept at home in cash, in tansu savings, named for the traditional wooden cupboards in which people store their possessions. But from the early 2000s, the housewives - often referred to collectively as "Mrs Watanabe", a common Japanese surname - began to hunt for higher returns.
Many were dissatisfied with the paltry interest rates banks were offering. The 0.02 per cent return on a typical fixed-term deposit was so derisory that the annual payment on even substantial lifetime savings might come to a mere few hundred yen. "If you got a puncture on the way to the bank, you'd be out of pocket," scoffs Ishiyama. She, like hundreds of thousands of others, found more appealing returns in foreign bonds and other overseas investments. "I was walking in the street and I saw a poster advertising a 5 per cent interest rate. I got quite giddy with the idea," she says. "I saw TV advertisements with everyone grinning and I thought: 'I suppose it should be OK.'"