Japan's Nikkei average climbed 1.8 percent on Friday to its highest level in three weeks, gaining a foothold above 9,000 after bold plans for stimulus from the U.S. Federal Reserve boosted risk appetite and lifted battered cyclical stocks.

Miners and metal producers, which have a relatively strong correlation with the health of the global economy, rallied the most. The mining sector <.IMING.T> jumped 5.8 percent and non-ferrous metals <.INFRO.T> rose 5 percent.

The Nikkei <.N225> advanced 164.24 points to 9,159.39 in heavy volume, helping to hoist the benchmark well clear of its 200-day moving average at 9,002.87.

A senior dealer at a foreign bank said buy orders were outnumbering sell orders by a ratio of "between 2 and 2.5 to 1".

"A decent amount of flow, I would say ... not much hedge fund money but long-only primarily," he said, but added that currency moves, including the potential for intervention, remain a key concern.

"Japan is going to continue to underperform so long as the currency strengthens. The open question is whether the Bank of Japan is going to step in and actually do something to the currency," the trader said.

The first round of quantitative easing from the Fed helped the Nikkei surge 23 percent in the subsequent three months, and it climbed nearly 12 percent for the same period after the second dose of stimulus.

But the yen is much higher now, hitting a seven-month high of 77.13 yen against the dollar on Thursday. That compares with a level of around 95 yen to the dollar in the three months after the first QE and around 80-84 yen for the same period after the second round.