Mars Financial News: On March 23, escalating US-Iran tensions heightened market concerns, causing stock markets in Japan and South Korea to close sharply lower on Monday. According to market data, South Korea's KOSPI index closed down 375.45 points on March 23 (Monday), declining 6.49%, at 5405.75 points. Japan's Nikkei 225 index closed down 1857.04 points on March 23 (Monday), declining 3.48%, at 51515.49 points.