* MSCI Asia ex-Japan down 0.3 pct
* Nikkei jumps more than 4 pct to highest since August 2008
* Ten-year JGB yield hits record low
* Dollar, euro extend gains against yen
Japanese equities soared and the yen continued its tumble against the dollar and the euro on Friday after the Bank of Japan's unprecedented monetary expansion, but Asian shares eased ahead of U.S. jobs data amid rising concern over the American economy.
The MSCI's broadest index of Asia-Pacific shares outside Japan was down 0.3 percent, dragged lower by a 0.6 percent drop in Australian shares in early trade while South Korean shares slid further to fall 0.7 percent.
Japan's Nikkei stock average was again the outperformer, extending gains sharply to jump more than 4 percent soon after trading started, topping the 13,000 level for the first time since August 2008.
"Japanese stocks will likely continue outperforming its global peers as already high appetite from both foreigners and domestic investors has been boosted," said Yoshiyuki Kondo, an analyst at Daiwa Securities.
New Governor Haruhiko Kuroda committed the BOJ to open-ended asset buying and said the monetary base would nearly double to 270 trillion yen ($2.8 trillion) by the end of 2014 in a shock therapy to end two decades of stagnation.
"It means that the BOJ is deathly serious about their plans to reflate their economy," said Neal Gilbert, market strategist at GFT Forex, in a note to clients.
"There may not be too much action ahead of the almighty nonfarm payrolls release. While the overnight move was significant, this may be just the beginning and waiting for a pullback on them may mean you miss your last opportunity to join in."
The U.S. dollar and euro soared more than 3 percent against the yen on Thursday in their biggest one-day moves since 2008.
The dollar hit a fresh 3-1/2-year high of e to 97.06 yen early on Friday, while the euro rose to 125.50 yen , extending gains from Thursday.
Traders and analysts expect the yen to remain weak even if the U.S. dollar comes under pressure from signs of slowing growth. Risk assets were also seen supported by continued expansionary monetary stimulus from the world's major central banks.
The dollar index measured against a basket of major currencies hit an eight-month high on Thursday.
The U.S. nonfarm payrolls data due later in the session will likely show employers added 200,000 jobs last month after hiring 236,000 workers in February. The unemployment rate is seen steady at a four-year low of 7.7 percent.
But Thursday's report showed the number of Americans filing new claims for unemployment benefits hit a four-month high last week raised the risks for a weaker reading on the payrolls data.
The European Central Bank kept interest rates steady at its meeting on Thursday, as expected, sending European shares down sharply. Traders were unhappy at the lack of fresh economic stimulus measures from the ECB and took profits on recent outperformers.
But ECB President Mario Draghi said the bank stood "ready to act" because there was no certainty that the euro zone economy would pick up, leaving the door open for future rate cuts.
The euro was down 0.1 percent against the dollar at $1.2926 .
Concerns about the U.S. economy sent the benchmark 10-year U.S. Treasury yield down to near 3-1/2-month lows on Thursday, while the Japan's 10-year yield tumbled to a record low below 0.4 percent and 10-year Japanese government bond futures scaled a new historic high early on Friday.
Tensions on the Korean peninsula may weigh on sentiment.
U.S. crude inched up 0.3 percent to $93.50 a barrel.