Tokyo's Nikkei average ended down 5 per cent today in its biggest one-day percentage fall since the September 11th attacks in the United States.
The drop was caused by a steep Wall Street drop and a strong yen as investors nervously waited for Sony results right after the close.
The Nikkei average closed down 5.09 per cent at 10,335.16, breaking below 10,500 yen for the first time since October 9th.
The broad-based TOPIX index fell 5.28 per cent to 1,017.03, with heavy losses across a range of sectors.