In an elegant café overlooking Shiba Park in Tokyo, Ritsuko Shiono looks up from her book to check the foreign-exchange spot rates on her pink, sequin-dashed mobile phone. She is particularly interested in the Turkish lira. Meanwhile, 5,400 miles away in Ankara, the Turkish central bank is in panic mode because of Ritsuko – and the thousands of Japanese women like her who have quietly seized control of global currency markets.

Ritsuko, 34, is, as she puts it, “waist deep” in a fiendishly complex currency swap involving the Japanese yen, the US dollar and the Omani riyal. The trade has lost her more than 100,000 yen (£417) this morning alone. She is beginning to think she might get more joy from borrowing another 200,000 yen from her online broker and selling her yen for Turkish lira, but is irritated because the prices she’s after have not yet flickered on to her little screen.

To the growing horror of male Japan, when Ritsuko’s mind is not on the foreign exchange markets it is on stocks, bonds, property and other investment opportunities that might make her rich. She, and others like her, are blowing to smithereens one of Japan’s oldest taboos: in the emerging investment sisterhood, money is no longer a dirty word. In the past year eight new investment magazines have been launched to cater for them, and even their traditional fare of fashion and lifestyle titles have begun to incorporate sections on making money.

In the space of just a couple of years, Japanese online currency speculators – many of them housewives, elderly matriarchs or young working women – have taken the markets by storm. Economists, major corporations and investors, awed by the sheer market influence of the Japanese speculators, have been forced to rethink their analysis of global currency markets. James Gow, the British chief executive and co-founder of one of Japan’s big three internet currency brokerages, FXOnline Japan, says: “We are looking at Japanese women taking a very different attitude to risk and markets than they used to, and a lot of people have been taken by surprise by that.”

Borrowing their native yen more cheaply than any other major currency, multiplying their initial stake by as much as 200 times through margin trading and then dipping into dozens of higher-yield foreign exchange markets, the online traders of Japan now account for around $15 billion (£7 billion) of deals each day. Some have made the equivalent of hundreds of thousands of pounds in just six months’ trading, others trade with a fraction of that. They are, say currency analysts, “obsessive” sellers of the yen – relentlessly ditching the Japanese currency and its wafer-thin interest rates for the more lucrative currencies of New Zealand, Brazil, South Africa and Iceland. About a fifth of all trades that hit the screens at the Nomura brokerage are generated by “housewives” – the catch-all term the professionals use to describe Ritsuko and her powerful cohorts.

“Everyone seems so surprised that Japanese women are such energetic currency investors,” Ritsuko says, “but they really should have paid more attention to us. In an information economy, women are more powerful than men. We are the people who pay minute attention to tiny shifts in fashion and spend our lives online checking for gossip on the best restaurants and hotels.”

Ai, an investor from Nagoya in her late twenties, also argues that it is Japanese women’s ability to mine information that has now been transferred to the currency and stock markets. There are other advantages of their sex. While male online traders tend to close up their positions at 7pm and head out for a beer, she sneers, women just keep on trading. Some trade “spot forex”, dipping in and out of currencies around the world and playing directly on the volatility of markets to reap small gains. Others, by pumping up their initial stake via borrowings, take advantage of the differentials between overnight lending rates of various currencies: there is a lucrative difference between the 0.5 per cent rate for the yen and, say, the 8.25 per cent of the New Zealand dollar or the 17.5 per cent of the Turkish lira.

Turkey’s nightmare is that the Japanese housewives will lose interest and pull out of the lira, causing it to plunge. And it is not just the Turkish Government that is petrified by the Japanese housewives’ spectacular assault on its currency. Two months ago, when the New Zealand Government tried to intervene in currency markets by selling the dollar, its efforts were immediately and completely consumed by Japanese investors with virtually no effect on the exchange rate.

And as well as wrestling with the subversive, utterly unexpected cultural phenomenon of “greed is good” women, Japan itself has started to panic that this new breed of profit-hungry housewives threatens its economic revival and global standing. Because the housewives are endless sellers of the yen, any upward pressure on the Japanese currency is almost entirely absorbed by the online traders. For months now, the yen has fallen against most global currencies at every turn.

James Gow of FXOnline says: “Where the Government of Japan used to spend billions of dollars intervening in currency markets and fighting the prevailing tide to deflate the yen and help exporters, it now has thousands of Mrs Tanakas doing the same thing out of choice.” Although government intervention remains an option, things may be beyond immediate central bank control: individual Japanese have opened 600,000 margin trading accounts in the past year, with the deposits on those accounts amounting to around $5 billion.

One of FXOnline’s customers is Yoshie Akai, a 70-year-old grandmother from Kobe who has been an avid trader of forex for three years. She woke last Friday morning to find that she had lost about 8 million yen (£33,000) overnight. With more sangfroid than the most ruthless Wall Street dealing-room shark, she was trading again by mid-morning. “I was depressed in the morning. But if I leave this as it is, I will just be a loser. I’ll recover from this disaster,” she says. “I used to know when to buy. Now I’ve learnt the hard way when you should sell. You get a different sense of reality and risk when it is just numbers on a computer, not a bundle of notes sitting in front of me.”

Akai is one of two types of women traders emerging in Japan. One is the traditional holder of the family purse-strings. The once cautious housewife who routinely and unquestioningly used to deposit the family salary into postoffice savings (or might occasionally be tempted into a conservatively managed mutual fund) has decisively lost her faith in the strategy that she was told would ensure financial security. Ten years of near zero interest rates have shattered her trust that “Japan will provide”. She feels let down by Japan and she is looking for ways to make enough cash for a big holiday, or perhaps a new car.

The other is a totally new breed of investor: young women in their twenties and thirties using their own salaries to gamble on currencies or stocks and driven by the desire to make money fast. Their ambitions go far beyond a new handbag or a foreign trip. They want houses, fast cars and a lifestyle that has little in common with the thriftiness and self-denial preached by their mothers.

Both types fill the teaching room of the advanced investment class at the Nagoya financial school – a course designed for, and taught by, women. Yuko Kuriki, the instructor, says women want to use the markets to assert their independence as thinkers and create their own financial security. “Japan certainly has a sense of embarrassment about individuals getting rich but people have come to realise that without risk, you can’t get anywhere so there is a shift from savings to investment. Some women are now risking the family savings on stocks and forex: some are worried about their future, others are unashamedly greedy,” she says. “We are a culture that is traditionally most concerned with not losing money, rather than making lots of it. But the country has offered no yields for a decade so we have had to become investors.”

One of her students, 58-year old Etsuko, took to the markets after her husband killed himself during Japan’s financial crisis of 2003. “Japan has let us down, and I have to invest to make a living,” she says.

Sitting on the desk in front of Etsuko, 27-year old Ai represents the more aggressive face of Japanese women investors: “I want to challenge my lack of capital. I want to buy my own house and I’m a better investor than my husband. The markets offer me a sort of empowerment,” she says.

Proud of her class, Ms Kuriki stresses that her students, by the time she has finished with them, are not simply haphazard stock-pickers. “They are not like a lot of men. Women sell quickly when shares start falling, but they are much quicker than men to get back into the market and start buying again on the dips. Men decide on the basis of theory or past experience. Women look at the fundamentals.”

A yen for trade: Ritsuko’s day

7am: Ritsuko decides on two currency bets. She has 100,000 yen (£417) in her online trading account and the brokerage will lend her ten times that.

8am: She studies the Nikkei and Bloomberg and reckons the euro will rise

8.15am: She borrows 500,000 yen. (cheaply: the overnight interest rate is just 0.5 per cent), goes on to the spot foreign exchange market and buys euros at one euro per 160 yen.

8.30am: A medium-term bet: she borrows another 500,000 yen and buys New Zealand dollars, which will earn 8.25 per cent interest.

12 noon: Lunch and shopping (there are sales at Furla and Max Mara).

5.31pm: She was right: the euro is up 1 per cent. She buys back her yen, this time getting 176 yen per euro. After brokerage fees, her profit is around 5,000 yen – which about pays for her lunch.

2 months later: Ritsuko believes the Icelandic krone will be more lucrative than her New Zealand dollars. She exits her position with one sixth (two months out of 12) of the 8.25 per cent annual interest on the NZ dollars, pocketing around 6,100 yen – which she immediately churns into her next trade.

How currency trading works, and how to do it here

There is nothing to stop British investors doing exactly what their Japanese counterparts are doing. Those who decide to dabble in the foreign exchange markets don’t have to trade sterling just because they live in Britain. Instead they can decide to sell yen and buy New Zealand dollars, replicating the move that has been so profitable for Japanese investors.

Traditionally, British investors have been reluctant to play the currency markets. Investing in companies through the stock market has always been more popular than buying euros or yen. Experts say that investors feel safer in the knowledge that shares are likely to increase in value over the long term. Currency trading tends to be more short-term. Making money depends on selling one currency to buy another on the expectation that it will rise or fall. In effect, investors are betting on the points or “pips” between the price at which they buy currency and the price at which they sell. Each penny is worth one hundred pips. An investor must take a “postion”; in other words speculate on which way a currency will move. If they predict it will rise and it does, they will earn money. If it falls, they are liable for the difference. An investor who last week took a position that the dollar would rise would now be counting his earnings, as the price of buying a pound fell from $2.06 to $2.03 or by 300 pips, between July 24 and 27.

Alternatively, investors can choose to sell the currency of a country where the interest rate is very low to buy a currency of a country where the interest rate is high. In effect, they are borrowing currency at a low rate of interest and holding currency earning a high rate of interest. This is called a carry-trade. Each night an investor holds this position, they will receive a payment equal to the difference in the interest rates. But this can be risky as any fluctuation in either currency could result in all gains being wiped out.

There are signs that currency trading is becoming a more popular pursuit. Last year Deutsche Bank launched an online currency trading platform for private investors. It says that since then there has been a significant increase in the number of British investors trading currency. Customers need a $5,000 (£2,460) deposit to open an account.

Investors can also take a punt on the currency markets via spread-betting firms such as City Index or Capital Spreads. Tom Hougaard, chief market strategist at City Index, said: “Currency trading is as easy as walking down to Tesco and buying a can of beans. You can be up and running online within 15 minutes.” But the ease with which investors can get trading shouldn’t overshadow the risks. “It is quite daunting how much leverage you can get. This means you can buy a relatively big position with a small deposit,” Hougaard said. City Index allows customers to buy a position up to 50 times bigger than the funds that they have available. For example, those who dsposit £100 can take out a position worth £5,000 in their chosen currency. At Deutsche Bank, investors can trade up to 100 times the value of the cash they have available depending on their experience of currency trading. But just as your buying power is magnified, so are any potential losses. Investors who do not bail out of a poorly performing currency position in time may lose all the cash they deposited.

— GRÁINNE GILMORE

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