Speaking shortly after the yen hit 160 on Monday, Koll said any intervention "will be a waste of Japan's national assets" as the country sells its U.S. dollars to buy yen. Koll said the yen could ...

You could, for example, switch your debt out of pounds and into yen with the pleasing result that your monthly interest payments on a debt of £300,000 would fall from £1,500 a month to £250 ...

In both cases, authorities buy or sell yen, usually against the dollar. The Ministry of Finance decides when to step in and the Bank of Japan acts as its agent. The decision is highly political ...