Japanese shares opened lower Tuesday after falls on European and US markets and as investors booked profits following a recent surge in Tokyo stocks. The Nikkei index at the Tokyo Stock Exchange lost 0.50 percent, or 52.93 points, to 10,546.08 in the first minutes of trade. The Nikkei jumped 2.82 percent on Friday, the first trading day of 2013, after ending 2012 at its highest level since the 2011 quake-tsunami disasters, which sparked the worst nuclear crisis in a generation. Investor sentiment had been affected by weakness on European and US bourses, analysts said. \"The market remains overheated after running up so much over the past several weeks, making it vulnerable to more selling,\" SMBC Nikko Securities general manager of equities Hiroichi Nishi told Dow Jones Newswires. But a weaker yen should prevent the market from plunging. \"Currency levels remain somewhat supportive... so this should hold any sharp sell-offs in check,\" Nishi said. On Monday the Dow Jones Industrial Average shed 50.92 points (0.38 percent) at 13,384.29 on profit-taking ahead of the start of the corporate earnings season. The broad-based S&P 500 fell 4.58 points (0.31 percent) to 1,461.89, while the tech-heavy Nasdaq Composite edged down 2.84 (0.09 percent) to 3,098.81. Europe\'s main stock markets also fell. In the forex market, the dollar stood at 87.37 yen, softer from 87.89 in New York on Monday afternoon. The euro bought $1.3119 and 114.63 yen, mixed from $1.3115 and 115.09 yen in New York.