The key 225-issue Nikkei index closed at its lowest level in six years Thursday as investors continued to be spooked by falling share prices worldwide, the Russian ruble crisis, and uncertainty over Japan's weakened banking industry.

The stocks of all 19 major banks fell for the second straight session. Hitachi, Toyota Motor and Sharp all dropped to new lows for the year due to increasing fears of a worldwide price deflation.

The key Nikkei index fell as low as 14,378.67, its lowest intraday level since July 3, 1995, when it sank to 14,295.90. But buybacks helped the index regain some lost ground, and it ended down 452.24 points, or 3.04 percent, at 14,413.79.

It was the Nikkei's lowest close in the post-bubble economy era since finishing at 14,309.41 on Aug. 18, 1992. The Topix index of all 1,333 first-section issues also slumped to its lowest close in six years. It ended at 1,116.97, down 30.24 points, or 2.64 percent. "The morning session was an exasperating one," said Hideo Suzuki, president of New Japan Securities Research Institute, as the Nikkei also sank below the 25-year moving average of 14,570.60. Volume on the major section inflated to 505.63 million shares, up from 412.26 million Wednesday.

Long-Term Credit Bank of Japan, attempting to merge with Sumitomo Trust & Banking, fell 1 yen to 51 yen after dipping to an intraday low of 48 yen. Sumitomo Trust ended down 13 yen, or 3.67 percent, at 351 yen after hitting a low for the year of 343 yen in the morning.