Japanese shares hit a 15-year high on Wednesday after the Bank of Japan maintained its asset purchase programme in an effort to boost the economy.
In Tokyo, benchmark Nikkei 225 index closed up 0.8% at 19,789.81 – its highest level since April 2000.
The central bank has kept its policy unchanged since expanding stimulus in October to deal with the impact of lower oil prices and easing inflation on Japan’s growth.
In China, shares hit a seven-year high.
Hong Kong’s Hang Seng index closed up 3.8% at 26,236.86, the highest level since May 2008. The percentage gain was the biggest since December 2011.
It was also the first time Chinese investors used the entire 10.5bn yuan ($1.69bn) daily investment quota in the stock connect scheme that allows them to buy stocks in Hong Kong from Shanghai and vice versa.
Analysts said the surge in interest was triggered by Beijing’s move last week to let mutual funds invest in Hong Kong via the connect plan.
The Shanghai Composite Index finished up 0.9% at 3,994.81.
Shares of train makers China CNR and CSR jumped over 42% after they received regulatory approval to merge. The plans were first announced in December.
Their shares had been suspended from trading since 30 March.
In Australia, the benchmark S&P/ASX 200 index closed up 0.6% at 5,960.7.
Shares in ANZ fell 0.3% despite news that the bank had won an appeal against a court ruling that some of its credit card fees were unfair, after thousands of customers launched Australia’s biggest class action lawsuit.
In South Korea, the benchmark Kospi index ended up 0.6% at 2,059.26 – its highest close since September.