The Nikkei 225 became the main symbol of Japan’s asset-price bubble collapse after reaching its peak in 1989.
The index reached an all-time closing high of 38,915.87 on December 29, 1989. That peak came after years of rising Japanese share and land prices, supported by easy credit and strong investor optimism. The bubble then burst, and equity and property values fell dramatically.
Japan entered a prolonged period of weak growth, banking problems, and deflation that is often called the Lost Decades. The Nikkei remained far below its 1989 peak for many years, making the episode a major example of how a stock-market crash can have lasting economic effects.
The TOPIX is another important Japanese index, but it tracks a broader section of the Tokyo Stock Exchange. The Nikkei 225 is the more widely recognized headline gauge.