Index heavyweight Softbank added 2.7 percent after paying $1.26 billion for a majority stake in Brightstar, a New York-based distributor of mobile phones.
The index rose above 14,640 points to close at its highest levels since September 27.
Shanghai 1.6% higher
China's benchmark index accelerated gains to hit a one-week high after Premier Li Keqiang stressed the importance of maintaining reform implementation at a State Council meeting on Sunday.
Fosun Pharmaceutical Group surged by the maximum daily limit of 10 percent after its subsidiary entered a licensing agreement with Switzerland's SELLAS Clinical.
Real-estate developers erased earlier gains to rally ahead of the nation's monthly house price index. China Merchants Property rose 1.5 percent while Shanghai Shimao added nearly 2 percent.
(Read more: Asia's commercial property deals set for record year)
Sydney rises 0.6%
Australian equities rose above the 5,330 mark to hit their highest levels since 2008 for a second straight session thanks to strong gains in miners.
Sundance Resources surged 28 percent, extending last week's strong rally. The miner released a statement to the ASX last week saying it is not aware why shares have been trading so heavily.
BHP Biliton rose 1.4 percent ahead of releasing quarterly production figures on Tuesday while Fortescue Metals rallied 3 percent.
Qantas Airways skidded 5.6 percent after flagging rough business conditions on Friday.
South Korea's benchmark index closed at its highest level since March 2012 and traded 5 percent above its 200-day simple moving average (SMA) of 1,949 points.
Samsung Electronics fell nearly 0.5 percent ahead of rival Apple's new iPad release on Tuesday.
LG Chemical lost 3.4 percent after announcing a 14 percent annual fall in third-quarter operating profit on Friday.
(Read more: Emerging markets poised for further rally: BofA-ML)
India's benchmark index moved off a new three-year high of 20,932 points as the rupee weakened half a percent to 61.5 per dollar.
— By CNBC.com's Nyshka Chandran. Follow her on Twitter @NyshkaCNBC