The Nikkei 225 lost about 63% from its 1989 peak during Japan's asset-price crash.
Japan's extraordinary late-1980s boom pushed the Nikkei 225 to an all-time closing high of 38,915.87 on December 29, 1989. The boom was supported by soaring property and share prices, easy credit, and optimistic expectations about Japanese corporations.
After the bubble began to deflate, the index fell steeply. It reached a low near 7,055 in March 2009, representing a decline of roughly 82% from the 1989 peak. The resulting period of weak growth and financial stress became known as Japan's Lost Decades.
The Nikkei 225 is not Japan's only major market gauge: TOPIX covers a broader group of companies listed on the Tokyo Stock Exchange. The 63% figure describes the fall to an early-1992 level, while the eventual trough was much deeper.