The spot yuan opened at 6.2276, its strongest permitted intra-day level, and stayed there through to early afternoon, unable to recapture Wednesday's record-strong close of 6.2252.
The People's Bank of China (PBOC) set the daily midpoint at 6.2905 versus Wednesday's 6.2881, the first time it has weakened the midpoint in eight days.
Under China's managed float regime, the exchange rate can diverge 1 percent either side of the midpoint fix, set by the central bank each day.
The spot yuan has set new records every day in the previous seven trading days by changing hands at the strongest rate allowed by the midpoint fixing, as the market strained at the central bank's leash.
Traders said the yuan's strength has been driven primarily by corporates unwinding long-dollar positions accumulated in the first half of the year, aggravated further by unexpectedly strong October exports which pumped more dollars into the system.
But economists expect the rally to end by early 2013 as PBOC moves to mop up excess dollars and a seasonally driven surge in exports subsides.
Many dealers have complained that trading volumes have been badly hit by the lack of two-way movement in the exchange rate, combined with uncertainty over how the PBOC would act once the Communist Party Congress winds down following the unveiling of a new leadeship on Thursday.
A trader at a joint-stock bank in Shanghai said that dollar buying was creeping back from a few customers, but he was unsure if it was genuine demand or the central bank had prodded them into buying.
"It could be that they need dollars, or it could be a decree from above," he said.
Despite the yuan's swift rise in recent months, forward yuan is still trading at a discount both on and offshore.
While some analysts interpret this as a sign that the market expects the yuan to give back recent gains, others say forward prices are increasingly determined by the interest rate differential between yuan and dollars as China gradually loosens controls on cross-border capital flows.