Asian currencies retreated from highs on Friday, following the yen's moves as markets reassessed speculation that Japan would moderate its currency intervention.
The dollar was almost a yen up from Thursday's one-month low of 106.35 per dollar. Late on Thursday it was hurt by security concerns after a bomb scare affected train services between Britain and France.
News that a senior al Qaeda member may have been cornered in Pakistan boosted the dollar, as did a view that the yen's nearly six percent rally in 10 days may have been too rapid.
The Singapore dollar fell back to 1.6920/30, levels seen in Thursday's Asian trading and down from the 1.6861 highs struck in offshore deals.
The Korean won gave up four won from an offshore one-month peak near 1,155 per dollar. The Taiwan dollar was also off a one-month high, of 33.16 per dollar, and treaded warily ahead of Saturday's presidential elections.
Analysts said the sluggishness in currencies was a sign markets had got ahead of themselves in buying the yen, and were now wary.
"I am convinced that a $50 billion a month run rate of (Japanese) intervention is utterly unsustainable and unwise and that we have seen the peak," said David Simmonds, markets strategist with the Royal Bank of Scotland, Singapore.
"The problem is the temptation to look for extremes, that either they continue at the same extraordinary rate of intervention that they have shown over the last few months, which is ridiculous, or that they suddenly disappear altogether," he said.
The other Asian central banks were also likely to intervene less, although they would remain watchful ahead of elections in many countries, Simmonds said.
"I do feel we are in the early stages of a shift in balance here, away from such huge levels of intervention and reserves accumulation and towards a slightly faster pace of currency gains," Simmonds said.
"But I am quite sure that CBC (Taiwan's central bank), BpK (Bank of Korea), MAS (Monetary Authority of Singapore) are still vigilant around the fringes of these markets and they are not going to disappear either."
The Thai baht rose in a belated catch-up with the region's up-trend but the Indonesian rupiah was weighed down by uncertainty ahead of that country's long election period, which begins next month.
Bhanu Baweja, currency strategist with UBS, said while the Korean authorities were managing the won less closely than before, they would not let it trade freely until investment and employment improved.
Moreover, there was a threat from the recent drop in leading indicators for Asian exports, he said.
"If this situation does not change soon, and growth in Korean export incomes begins to slow even when domestic economy recovery has not yet shifted into top gear, it will induce the authorities to once again be more interventionist in the market," Baweja said.