The index got off to a strong start tracking overnight gains on Wall Street. The Dow added 0.83 percent and the tech-heavy Nasdaq climbed 1.72 percent.

The market trimmed earlier gains but managed to maintain the momentum throughout the session as institutions turned net buyers and buying by individual investors was solid.

"The US market closed higher on chip shares and as Apple rebounded, which affected the local stock market in a positive way," said Seo Sang-young, an expert at Kiwoom Securities.

"Increased hopes for an eased trade war between the U.S. and China were also a positive factor."

The media reported that China has delivered a written response to the U.S., affecting investors' sentiment that possible negotiations could lead to an end of the ongoing trade friction between the world's two largest economies.

Large caps on the KOSPI were mixed at the close.

Top cap Samsung Electronics ended at 44,000 won, down 0.56 percent, and global chipmaker SK hynix lost 2.37 percent to close at 70,100 won.

Top-cap bio and telecom shares, meanwhile, traded higher, with pharmaceutical giant Celltrion surging 2.52 percent to end at 224,000 won to continue a three-day winning streak.

Mobile carriers closed in positive terrain, with No. 1 player SK Telecom jumping 4.49 percent to 279,000 won and second-largest KT inching up 0.17 percent to 29,950 won. LG Uplus, the smallest in the country, was up 0.66 percent to 15,350 won.

The local currency closed at 1,128.5 won against the greenback, up 0.7 won from the previous session's close.

Bond prices, which move inversely to yields, ended mixed. The yield on three-year Treasurys added 0.4 basis point to 1.947 percent, and the return on benchmark five-year government bonds was down 1.6 basis points to 2.055 percent. (Yonhap)