The benchmark Korea Composite Stock Price Index shed 4.19 points, or 0.18 percent, to 2,322.43 in the first 15 minutes of trading.
Steelmakers got off to a weak start, with No. 1 player POSCO falling 1.61 percent and second-largest Hyundai Steel losing 1.05 percent.
Top carmaker Hyundai Motor decreased 0.72 percent, and its sister Kia Motors moved down 1.32 percent. Auto parts maker Hyundai Mobis stood unchanged from the previous session.
Market behemoth Samsung Electronics, on the other hand, advanced 0.13 percent.
The local currency was trading at 1,131.95 won against the US dollar, down 0.85 won from the previous session's close. (Yonhap)