Is the Japanese stock market the nightmare of long-term investors? No. Investors who avoided the bubble-period reached a decent 3.9 real return p. a. Because of the currency appreciation, the return was higher in dollar terms. Japanese stocks in USD hit even new all-time high already.
Are Japanese stocks still a good buying target? There are some positive arguments. Japan has so far successfully solved problems of the pandemic, so the infection numbers stay moderate. The Bank of Japan keeps its easing policy, and it is unlikely to change in the next few years. The Japanese economy is benefiting from the progress of other, fast-growing Asian countries like China.
But the valuations of the Japanese shares are also high. The CAPE Ratio (modified P/E ratio or Shiller P/E) was 24.26 on December 31. This indicator reached 33.44 in the USA, but only 22.82 in Canada, 18.1 in China, 14.1 in Hong Kong, and 13.66 in the United Kingdom. (By data of Siblisresearch.) So, it may be easier to find cheap stocks elsewhere.