Tokyo stocks edged up 0.12 percent to close at their highest level since last year's earthquake-tsunami disaster, helped by a weaker yen and receding worries over the eurozone debt crisis.
The Nikkei 225 index at the Tokyo Stock Exchange gained 12.16 points to close at 10,141.99, the highest level since March 11 last year when the index finished at 10,254.43.
The Topix index of all first-section issues rose 0.19 percent, or 1.62 points, to 868.35.
The Nikkei rallied after the euro briefly rose past 110 yen early Monday, Mizuho Securities senior technical analyst Yutaka Miura told Dow Jones Newswires.
Receding worries over the eurozone debt crisis and some upbeat US economic data also provided support for the index, brokers said.
The dollar was hovering around 83.40 yen in afternoon trade, almost unchanged from late Friday in New York.
"Since the yen is still weaker, the (Nikkei) index is unlikely to face a big price adjustment," Daiwa Securities senior market analyst Yumi Nishimura said.
Lacklustre trading was expected ahead of Tuesday's public holiday in Japan and concern about US housing data to be released later in the week, brokers said.
Marubeni was up 2.39 percent at 641 yen after reports the Japanese trading firm was in advanced talks to buy a stake in the massive Roy Hill iron-ore project in Western Australia.
Shares in Fanuc, a factory automation systems maker, rose 1.97 percent to a near-record 15,500 yen, thanks to the Japanese currency's weakness and the company's exposure to the booming smartphone industry.
Other Asian shares were also mostly higher Monday, with Sydney adding 0.34 percent, or 14.6 points, to close at 4,290.8 and Seoul ending 0.62 percent higher, adding 12.56 points to 2,047.00.
Hong Kong was 0.31 percent higher but Shanghai slipped 0.56 percent.
Global investors have grown bullish in recent weeks after Greece agreed a debt write-down with private creditors qualifying it for a bailout while the US has also provided weeks of good news that point to a brighter future.
"It seems traders are becoming more bullish with every week that passes," said Justin Harper, markets strategist at IG Markets in Singapore.
"With a total eurozone meltdown in the rearview mirror and a US economic recovery gaining traction there is plenty to be positive about," he said in a note to clients, according to Dow Jones Newswires.
In other markets:
-- Taipei fell 0.14 percent, or 11.02 points, to 8,043.92.
Hon Hai Precision was 0.48 percent lower at Tw$104.0 while Taiwan Semiconductor Manufacturing Co gained 3.21 percent at Tw$83.7.
-- Wellington fell 0.54 percent, or 19.05 points, to 3,485.97.
Fletcher Building was down 1.6 percent at NZ$6.78, Telecom shed 0.4 percent to NZ$2.45 and Sky City was 1.8 percent lower at NZ$3.91. Air New Zealand gave up 1.7 percent to end at NZ$0.865