The Nikkei stock index gained 0.25 percent to close at a fresh eight-month high Friday, as the yen's ongoing retreat against the U.S. dollar kept the market buoyant despite Wall Street's closing low overnight, but geopolitical concerns over the Russia-Ukraine situation capped the market's upside.
The Nikkei 225 index added 39.09 points to close the week at 15, 948.29, marking its best close since early January, while the broader Topix index of all first-section shares gained 0.19 percent, or 2.48 points, to finish at 1,313.72.
Local strategists said a broad range of issues attracted buying in the morning session as the U.S. dollar traded in the 107 yen zone, a boon for explorers with a wide exposure to overseas markets who see their profitability and earnings outlooks boosted when the yen is weak.
"The weakening of the yen is set to continue for the time being, given the strength of the U.S. economy pushing up the dollar and also the expectations for further easing in Japan," Tetsuo Seshimo, a portfolio manager at Saison Asset Management Co. said.
"Foreign investors see a weaker yen as equalling higher stocks, so we're seeing a spiral in which shares rise as the yen drops," he said.
But following the market's four-day winning streak, some investors opted to sell for gains in later trade and square away positions before the weekend here.
But while there were positives underpinning the market on the last trading day of the week, like Bank of Japan (BOJ) Governor Haruhiko Kuroda telling Prime Minister Shinzo Abe Thursday that he would widen the central bank's monetary base if it looks like the bank will fail to hit its two percent inflation target by next year, there were negatives too.
U.S. President Barack Obama pledging more air strikes on Islamic State extremists and saying the U.S. is joining the European Union in slapping more sanctions on Russia for its continued support of separatists in Ukraine, renewed geopolitical concerns about these regions' potential to disrupt global markets.
But with the weak yen leading the way, automakers led the charge, with Toyota Motor adding 1.4 percent to 6,303 yen, while Yamaha Motor gained 2.2 percent to 2,087 yen. Fuji Heavy Industries, for its part, jumped 2.6 percent to close the week at 3,188 yen.
Consumer electronics behemoth Sony climbed 1.1 percent to 2,127 yen, following Disney and Fox saying they would join Viacom in providing Sony with web-based TV content. Viacom initially said it would provide 22 television stations to Sony's web-based service was an unprecedented move by the American global mass media company.
Konami, a game software developer, was also in the spotlight Friday, jumping 1.3 percent to 2,285 yen, following Morgan Stanley MUFG Securities Co. lifting its investment rating on the firm's stock.
Trading volume on Friday increased to 2.74 billion shares on the Tokyo Exchange's First Section, up from Thursday's volume of 2. 13 billion shares, with declining issues trumping advancing ones by 913 to 765.