At 06:30 GMT, the KOSPI closed higher 9.48 points or 0.39 percent at 2,445.85. For the week, the index gained 1.2 percent, while ending March with 0.8 percent gain.
Hyundai Mobis and Hyundai Glovis shares lost 5.7 percent and 7.1 percent, respectively, with Mobis hurt by worries that its parent group's restructuring plan will disadvantage Mobis shareholders.
The won was quoted at 1,063.5 per dollar on the onshore settlement platform, 0.23 percent firmer than its previous close at 1,065.9. The currency strengthened 1.8 percent on the week, its biggest weekly percentage gain since mid-November.
It rose 1.8 percent on the month.
In offshore trading, the won was quoted at 1,062.58 per US dollar, down 0.05 percent from the previous day, while in one-year non-deliverable forwards it fetched 1,048.4 per dollar.
MSCI's broadest index of Asia-Pacific shares outside Japan was up 0.24 percent, after US stocks ended the previous session with gains. Japanese stocks rose 1.4 percent.
The KOSPI is down around 1.3 percent so far this year, and up by 2.14 percent in the previous 30 days.
The current price-to-earnings ratio is 12.10, the dividend yield is 1.28 percent and the market capitalisation is 1,242.04 trillion won.
The trading volume during the session on the KOSPI index was 390,118,000 shares, and of the total traded issues of 885, the number of advancing shares was 646.
Foreigners were net sellers of 171,752 million won worth of shares.
The US dollar has fallen 0.36 percent against the won this year.
The won's high for the year is 1,056.67 per dollar on January 14 2018 and low is 1,098.4 on February 6 2018.
In money and debt markets, June futures on three-year treasury bonds rose 0.02 points to 107.72.
The Korean 3-month Certificate of Deposit benchmark rate was quoted at 1.65 percent, while the benchmark 3-year Korean treasury bond yielded 2.218 percent, lower than the previous day's 2.23 percent.