* Investors unwind risk-off positions on weak yen - analyst * Volume may be subdued before widely focused U.S. jobs data analysts By Ayai Tomisawa TOKYO, March 7 (Reuters) - Japan's Nikkei share average rose to a new five-week high on Friday morning as a weak yen lifted risk appetite following Wall Street's gains on better-than-expected U.S. jobless claims and the European Central Bank's decision to keep its rates unchanged. The Nikkei gained 1.1 percent to 15,307.78, the highest since Jan. 29 after rising 1.6 percent on the previous day. For the week, the index has added 3.1 percent. Exporters advanced as the dollar fetched 103.100 yen, having broken above the 103 yen threshold on Thursday for the first time since late January. "Investors are unwinding their risk-off positions as they were waiting for the dollar to trade above 103 yen as it has been hovering below that level lately," said Nobuhiko Kuramochi, a strategist at Mizuho Securities. Sony Corp gained 1.5 percent, Tokyo Electron Ltd added 1.7 percent and Canon Inc rose 0.9 percent. A weak yen lifts Japanese exporters' competitiveness abroad as well as their profits overseas when repatriated. The euro traded 142.87 yen after brushing a two-month high of 142.99 yen after the European Central Bank left its interest rates unchanged. The Topix rose 0.7 percent to 1,236.45, with 30 of its 33 subsectors in positive territory. Analysts said the rally in the stock market may continue throughout the day, but volume may be subdued before the release of widely anticipated U.S. jobs data later in the day. Weekly applications for U.S. unemployment insurance fell to 323,000, the lowest in three months, a sign of strength in a labour market that has been hobbled by severe weather. Friday's nonfarm payrolls report, due at 8:30 a.m. EST (1330 GMT), is expected to show job growth in the United States picked up enough in February to encourage the Federal Reserve to continue scaling back its monetary stimulus. The JPX-Nikkei Index 400, an index launched this year comprising firms with high return on equity and strong corporate governance, advanced 0.7 percent to 11,193.43.