Asian markets mostly fell Friday on concerns over the US economy, but Tokyo enjoyed a second straight rally and the yen slipped after the Bank of Japan unveiled a vast plan to boost the economy.
Japan's Nikkei surged more than four percent in early trade to its highest level since August 2008, a day after the BoJ's stimulus aimed at bringing years of deflation to an end.
However, profit-taking later in the day meant the rally petered in the afternoon, while the yen regained slightly after suffering a big sell-off in the wake of the bank announcement.
By the end of trade the Nikkei index closed 1.58 percent higher, adding 199.10 points to 12,833.63, still its best close since September 1, 2008, weeks before the global financial crisis rocked markets.
Other regional markets struggled as jitters set in over the US economy and tensions on the Korean peninsula.
Seoul closed down 1.64 percent, 32.22 points, at 1,927.23, a day after falling 1.20 percent. Sydney lost 0.45 percent, or 22.1 points, to end at 4,891.4
In the afternoon Hong Kong was off 2.39 percent, with traders also concerned about a number of bird flu deaths in mainland China, which rekindled memories of the SARS outbreak in 2003.
Shanghai and Taipei were closed for a public holiday.
In the first meeting under new governor Haruhiko Kuroda, the BoJ announced a doubling of the money supply and aggressively increased asset purchases, while vowing no let-up in the battle against falling prices.
The move immediately sent the yen diving and exporters soaring, lighting a fire under the Nikkei. Investors continued the trend on Friday.
"Foreign investors now have no choice but to buy Japanese stocks," said Kenichi Hirano, market analyst at Tachibana Securities.
In Tokyo forex trade, the dollar rose at one point to 97.04 yen -- its highest since August 2009 -- from 96.33 yen Thursday in New York and way up from 92.71 yen before the BoJ measures were unveiled.
The euro bought 125.20 yen from 124.60 yen in New York and from 119.66 yen ahead of the announcement.
But in the afternoon in Tokyo the dollar sat at 96.31 yen and the euro bought 124.41.
The euro fetched $1.2924, compared with $1.2934 in New York.
While Japanese investors enjoyed a bumper session, the rest of Asia was grappling with a weak set of US data.
The Dow rose 0.38 percent, the S&P 500 added 0.40 percent and the Nasdaq climbed 0.20 percent but gains were capped by a disappointing report on US jobless claims, which unexpectedly rose 28,000 to 385,000 for the week ending March 30.
Those figures come as markets nervously await the release of key non-farm payrolls data later in the day, with expectations low after huge federal spending cuts came into force at the beginning of last month.
"Given that the US jobless claims data underwhelmed, there is concern the non-farm payrolls will follow suit, and add to the recent run of bearish signals," William Leys, Sales Trader at CMC Markets wrote in a note to clients.
"If this does occur, another sell-off is on the cards," he said, according to Dow Jones Newswires.
"On the other hand, a positive report may lead to a bounce against the recent downtrend and provide some welcome relief for equities across the board."
Adding to regional selling pressure is news that the United States said it was taking "all necessary precautions" after North Korea moved a medium-range missile to its east coast.
It was the latest move by Pyongyang which has issued a series of threats of nuclear war in recent weeks in response to UN sanctions and South Korea-US military drills.
Oil prices rose, with New York's main contract, West Texas Intermediate light sweet crude for delivery in May, shedding 13 cents to $93.13 a barrel while Brent North Sea crude for May rose seven cents to $106.41 in the afternoon.
Gold was at $1,551.80 an ounce at 0605 GMT compared with $1,544.90 late on Thursday.
In other markets:
-- Wellington ended flat, adding 2.81 points to 4,432.97.
Fletcher Building ended up 1.9 percent at NZ$8.76 and Telecom fell 2.4 percent to NZ$2.41.