The KOSPI gained 199.60 points, or 2.2 percent, to close at a record 9,063.8. Japan's Nikkei 225 rose 1.6 percent to 71,053.4, while China's Shanghai Composite traded around 4,092, down about 0.4 percent.
The surge was driven by semiconductor heavyweights from South Korea to Japan and China, highlighting how artificial intelligence-linked chip stocks continue to dictate the direction of North Asian equity markets.
SK hynix jumped 6.5 percent to 2,685,000 won (US$1,759), while Samsung Electronics rose 4.6 percent to 362,500 won ($237).
Samsung Electro-Mechanics climbed 8.2 percent to 2,200,000 won ($1,441), extending gains across South Korea's technology supply chain.
The strength in the country's largest chip and electronics stocks helped propel the KOSPI through a level that had long been viewed as a major psychological threshold for investors.
Japanese semiconductor shares also advanced sharply.
Tokyo Electron gained 4.7 percent to 76,080 yen, while Lasertec surged 7.1 percent to 56,450 yen. Advantest added 0.8 percent to 30,300 yen.
Chinese semiconductor stocks outperformed the broader market despite weakness in mainland indexes.
Cambricon jumped 14.5 percent to 1,512.2 yuan. China Tungsten & High-Tech rose 10 percent to 98.4 yuan, while Jingsheng gained 4.3 percent to 54.1 yuan.
The contrast between rising semiconductor shares and softer broader indexes reinforced a trend seen across the region this year, with investors concentrating capital in companies tied to artificial intelligence infrastructure and advanced chip production.
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