Nikkei gained 1% to top 20,000-point level for the first time since August 2015
US stocks ended little changed, with healthcare gains offsetting declines in energy
China's consumer price inflation slowed to its weakest pace in almost a year in August, missing expectations
Yen rose 0.6 per cent to one-month high of 100.60 to the dollar
Crude oil prices extended gains on hopes that big producers will cap production, improving investors' appetite for riskier assets