Japan's Nikkei Stock Average closed down 12.4% on Monday, a historic fall triggered by disappointing U.S. jobs data and a further rise in the yen. The index's drop followed a 5.8% fall on Friday. The Nikkei has given up all its gains this year and has dropped more than 25% since it reached a record high last month, putting it in bear-market territory. It was the biggest single-day percentage drop in the Nikkei since it fell 14.9% on Oct 20, 1987, after the "Black Monday" crash on Wall Street. Other stock indexes in Asia also fell, with South Korea's benchmark Kospi down 8%.