Several sharemarkets hit new highs during the first few months of this year, but the most significant milestone of all came in Japan, where the Nikkei 225 index finally retook the level it reached 34 years ago in 1989. After a stellar performance in 2023 which saw the Nikkei surge 28.2 per cent, even outpacing the mighty S&P 500, Japanese shares rose another 20.6 per cent in the first three months of this year and stormed through those previous highs. The rally hasn’t been because of a weaker yen and massive stimulus alone. We’ve seen a notable increase in governance standards, while valuations also look reasonable even after the gains of the past 18 months. Perhaps most importantly of all, Japan is finding its way back onto the radar of investors. After being ignored for decades, these recent positive developments might see Japanese shares increasingly included in portfolios as a diversification opportunity following big moves in US shares.