Japan's benchmark Nikkei stock index closed at a more than 21-year high on Wednesday as investors snapped up issues following solid earnings reports released a day earlier from Japan Inc. for the fiscal first-half.

The 225-issue Nikkei Stock Average added 408.47 points, or 1.86 percent, from Tuesday to close the day at 22,420.08, marking its highest close since July 1996.

The broader Topix index of all First Section issues on the Tokyo Stock Exchange, meanwhile, gained 20.75 points, or 1.17 percent, to finish at 1,786.71.

Local brokers said that robust earnings reports from some bellwether firms here like Sony Corp., as well as upwardly revised profit outlooks from domestic corporations, was the main impetus for buying.

Market strategists noted however that some investors hit the sidelines ahead of key events later this week, including U.S. jobs data, nominations for the new chair of the Federal Reserve and President Donald Trump's visit to Japan from Sunday.

Oil and coal product, air transportation and electric appliance-linked issues comprised those that gained the most by the close of play, and rising issues beat declining ones by 1,248 to 704, on the First Section, with 80 ending the day unchanged.

On the main section on Wednesday, 2,056.82 million shares changed hands, rising from Tuesday's volume of 1,888.01 million shares.

The turnover on the third trading day of the week came to 3,755.7 billion yen (32.98 billion U.S. dollars).