The beleaguered dollar struggled to recover from a fresh slump Friday triggered by a report on the probe into alleged Russian interference in the US election.
The greenback was under sustained pressure against the Japanese yen, testing 110 in afternoon forex trade, as it also fell against the euro with soft US economic data adding to negative sentiment.
Analysts warned it could go lower still with US wages data out later Friday unlikely to offer much relief.
The emboldened yen, seen as a safe haven currency, dragged down the Nikkei, which closed 0.4 percent lower. Toyota later announced upward revisions in full-year profit as it forecast a downturn in the yen.
Shanghai drifted lower by the close of play as Chinese stocks lost momentum after a record 2017 close on Tuesday, while Hong Kong edged higher.
Sydney stocks declined as the central bank cut its growth forecast and expressed concern over the local dollar's strength, but Seoul clawed back some losses endured Thursday after President Moon Jae-in announced plans to raise corporate taxes.
The revelation by the Wall Street Journal that special counsel Robert Mueller has convened a grand jury to investigate Russia's interference in the 2016 presidential election -- a step towards possible criminal indictments -- sparked a furious reaction from President Donald Trump and dented gains on Wall Street.
The Dow still edged to a record for the seventh straight day Thursday, although the tech-heavy Nasdaq retreated.
"In no small way this yen strength is related to news that broke overnight that Robert Mueller has empanelled a grand jury as he continues to look into the Russia issue -- as the president called it," said Greg McKenna, chief market strategist AxiTrader.
Stephen Innes, who heads Asia-Pacific trade at forex firm OANDA, noted: "Another toxic elixir for the greenback is brewing."
The turmoil in Washington is casting doubt on Trump's ability to push through an agenda aimed at boosting growth.
Traders were awaiting a key US jobs report that may provide clues on the strength of the world's top economy and the odds of an additional Federal Reserve rate hike this year.
But Chris Weston, Australia-based chief market strategist at IG Markets, cautioned the figures were unlikely to bolster the dollar.
"It's all about wages here, and ...specifically, if we can see more than a 30 basis points increase of wages (month-on-month) then perhaps, just perhaps, the USD can find some love," he said.
"It would be a big surprise though."
The dollar was also under pressure as a survey showed growth in the American services sector slowed sharply in July, shaking confidence in Friday's payroll data.
The euro, which had moved above $1.19 Wednesday for the first time since January 2015, was up against the greenback Friday at $1.1883.
The ailing US currency failed to bolster oil prices, which declined sharply on concerns American shale producers are ramping up production despite the persistent supply glut.
According to figures from industry agency Platts, the US rig count in July increased by 13 from the previous month.
"As far as the rise in production, that is something that definitely the bears are going to (latch) on to," said Phil Flynn, senior market analyst at Price Futures Group.
Europe's main stock markets lost ground at the start of trading on Friday, with London, Paris and Frankfurt all lower.
Key figures around 0820 GMT
Tokyo - Nikkei 225: DOWN 0.4 percent at 19,952.33 (close)
Hong Kong - Hang Seng: UP 0.1 percent at 27,562.68 (close)
Shanghai - Composite: DOWN 0.3 percent at 3,262.08 (close)
Euro/dollar: UP at $1.1883 from $1.1874
Pound/dollar: UP at $1.3148 from $1.3142
Dollar/yen: UP at 110.12 yen from 110.02 yen
Oil - West Texas Intermediate: DOWN 73 cents at $48.74 per barrel
Oil - Brent North Sea: DOWN 47 cents at $51.74
New York - Dow: UP less than 0.1 percent at 22,026.10 (close)
London - FTSE 100: DOWN 0.1 percent at 7,469.63 points