The conversation had a profound effect on the minister. Steeped in the orthodoxy that a weak currency was in Japan's national interest, he was struck by the force of the counter-argument, particularly since it came from an enthused consumer, the perennial weak link in Japan's economy. On that occasion there was no repetition of 2003, when Tokyo lavished funds on buying the US currency and undermining its own. In fact there was no intervention at all. The lady, presumably, was content.

Japan has returned to the yen debate. Only this time, the arguments are starker. In the past six months, the yen has strengthened from Y110 to Y90 against the dollar. Since July, it has appreciated by three-quarters against the shrinking pound.

That does not reflect the underlying strength of Japan's economy. Far from it – Japan has suffered a sharp contraction in industrial production and dwindling exports. As with the repatriation of funds to the US, where economic news is none too rosy either, investors have sought safety by bringing money back home. In Japan's case, this has been compounded by an unwinding of the so-called carry trade, through which investors borrowed cheaply in yen to invest in higher-yielding assets abroad. Now interest rate differentials with the US have narrowed to needle-eye dimension, those flows have stopped. The rising yen has pummelled Japanese share prices. Toyota, the bellwether of corporate Japan, last year suffered a 15 per cent drop in US sales. Now it is cutting thousands of contract workers and warning of a $1.5bn (€1.2bn, ￡1.1bn) operating loss, its first in decades.