The safe-haven yen held firm and riskier Asian currencies softened a little on Wednesday, as currency investors awaited the signing of the US-China trade deal with trepidation.
The formal agreement is aimed at drawing a line under 18 months of tit-for-tat tariff hikes that have hurt global growth, but it will not end the trade dispute between the world's two largest economy.
US Treasury Secretary Steven Mnuchin said existing tariffs on Chinese goods would stay, pending further talks.
That pulled China's yuan below Tuesday's six-month peak and lifted the Japanese yen from a seven-month low, as traders reckoned on few further benefits from the agreement.
"The deal is priced in," said National Australia Bank's head of FX strategy, Ray Attrill. "I can't see any reason why the yuan should continue to strengthen, given the limited amount of tariff rollbacks that are contained in this deal."
The yuan is the currency most sensitive to Sino-US trade relations, and it retreated 0.2% to 6.8942.
The yen was nearly 0.1% firmer at 109.88. The euro was steady at $1.1132 and the Swiss franc held on to overnight gains to sit at 0.9672 per dollar.
The trade-exposed Australian and New Zealand dollars each eased, with the Aussie last 0.1% lower at $0.6898 and the kiwi a fraction weaker at $0.6612. Against a basket of currencies the US dollar held at 97.339.
US President Donald Trump is slated to sign the Phase 1 trade agreement with Chinese Vice Premier Liu He at the White House at 1630 GMT.
Washington has already agreed to suspend tariffs on $160 billion of some Chinese-made electronics, and to halve existing tariffs on $120 billion of other goods to 7.5%.
But it will leave in place 25% tariffs on a vast, $250 billion array of Chinese industrial goods and components used by US manufacturers.
A source told Reuters that China has pledged to buy almost $80 billion of additional manufactured goods from the United States over the next two years under the deal, although some US trade experts called that unrealistic.
Mnuchin said deal documents will be released on Wednesday, except for confidential annex covering the product and services purchases.
Elsewhere the British pound was marginally stronger at $1.3027, ahead of inflation data due at 0930 GMT.
The consensus expectation is for the core annual inflation rate to hold steady at 1.7%. However, several recent hints at rate cuts from Bank of England policymakers have investors on edge that a miss on the downside may strengthen the case for monetary easing.
Money markets are now pricing in a 43% chance for a 25 basis point cut in rates at the end of this month.
"If we saw core inflation coming in at say, 1.4%, then I think that would inflame the situation," said Chris Weston, head of research at Melbourne brokerage Pepperstone.
He added that business surveys next week would be even more closely watched. "If they don't show any kind of meaningful rebound, then you're probably going to get a market that's pricing in (the chance of a cut) at north of 50%."