* Market upbeat as Wall Street shrugs off weak China survey * Chugai Pharma jumps after Citigroup raises rating * G20, discussion on Fed tapering impact in focus By Ayai Tomisawa TOKYO, Feb 21 Japan's Nikkei average jumped more than 2 percent on Friday, recouping most of the previous day's losses, as investors took heart from gains on Wall Street after a reading on U.S. manufacturing hit its highest in nearly four years. The Nikkei was up 2.2 percent at 14,765.67 in midmorning trade, moving closer to a 2-1/2-week high of 14,900.24 hit on Tuesday. The benchmark had fallen 2.2 percent the previous day, hit by a weak Chinese survey. Analysts said investors had shifted their attention back to U.S. growth from the Chinese economy as the U.S. market shrugged off the China flash Markit/HSBC Purchasing Managers' Index, which fell to a seven-month low in February. U.S. factory activity accelerated at its fastest pace in nearly four years in February, according to Markit's preliminary U.S. Manufacturing Purchasing Managers Index released on Thursday. "Investors realised that they overreacted to the China survey yesterday," said Hikaru Sato, a senior technical analyst at Daiwa Securities. "But we may not see further rises from here as people do not want to hold large positions before the weekend." Sato added that market participants were awaiting the outcome of the Group of 20 finance chiefs' meeting in Sydney this weekend, at which finance ministers and central bank chiefs are expected to discuss the impact on emerging markets from the U.S. Federal Reserve's stimulus tapering. Shares of exporters were strong, with Advantest Corp rising 3.4 percent and Panasonic Corp adding 3.2 percent. The dollar added about 0.1 percent to 102.33 yen, moving further away from the previous session's low of 101.65 yen and back towards a two-week high of 102.73 yen hit on Tuesday. Chugai Pharmaceutical Co, a subsidiary of Swiss drugmaker Roche Holding AG, soared 3.5 percent after Citigroup raised its rating to "buy" from "neutral", citing likely strong sales of Roche's trial-stage cancer treatment drug called MPDL3280A. The Topix added 1.9 percent to 1,194.56, with all of its 33 subsectors in positive territory. The JPX-Nikkei Index 400, an index launched this year comprising firms with high returns on equity and strong corporate governance, gained 1.8 percent to 11,002.70.