After being battered off and on for a couple years by European debt and U.S. political gridlock, China stocks have a new concern.

“Investors focus now is on Japanese Yen,” said Ben Kwong, chief operating officer at KGI Asia. “The extreme weakness of Japanese Yen triggered investors’ concern that it would hurt competitiveness of other Asian countries.”

The new worry has weakened China stocks for several days now, Kwong told Equities. On Friday the Hang Seng Index in Hong Kong sagged 0.08% to 23,580, down 22 points for the week. The index of Chinese companies fell 0.8% Friday, off 104 this week.

But the weak patch may be a buying opportunity, Kwong said, given that China’s economy appears to be gaining strength and a weak Yen is less damaging to China than it is to some other Asian countries like South Korea.

“Since China will remain invest heavily in the railway construction, we believe the sector will see argain-hunting interest at this price level,” he said. “Besides, CNY (Chinese New Year) is approaching, (and) it might trigger buying interest on mainland consumption plays and Macau gaming sector.