Japan's Nikkei 225 ended up 6.4% on Tuesday, rebounding from sharp declines in the morning that saw the index briefly break below 7,000 for the first time in 26 years. The Nikkei gained 459.02 points to 7,621.92. It earlier fell as much as 2.3% to 6,994.90, its lowest since 1982. The broader Topix rose 5% to 784.03 after falling 3% at one stage.