* Nikkei falls 0.9 pct, Topix sheds 2 pct * Gains in Fast Retailing, TDK help limit downside * BOJ to hold policy meeting on April 3-4 By Tomo Uetake TOKYO, April 1 (Reuters) - Japan's Nikkei share average fell to a two-week low on Monday morning as investors took profit after the benchmark posted its best quarterly performance in nearly four years. But expectations that the Bank of Japan will unveil aggressive monetary policy measures this week to revive the world's third-largest economy limited the fall. The Nikkei eased 0.9 percent to 12,283.75 by the midday break, after rallying 19.3 percent in January-March, marking its best quarterly performance since April-June 2009, as Prime Minister Shinzo Abe embarked on expansionary fiscal and monetary policies. "Selling led by the futures market pushed down the benchmarks today. Honestly, the decline was more than I expected," said Yuya Tsuchida, a strategist of Toyo Securities. "Although there wasn't any major market-moving events over the weekend, investors made pre-emptive moves to lock in profits in anticipation of bolder monetary easing announcements by the Bank of Japan this week." But the underlying trend remained positive, he said. Helped by the rally, Japanese equities now carry a 12-month forward price-to-earnings ratio of 14.2, a level not seen since July 2010 though still below the 10-year average of 16.4, according to Thomson Reuters Datastream. "There was a very large inflow (of programme trade) on Friday afternoon ... I reckon the fair value absent of that buying is at where we are," a senior trader at a foreign bank in Tokyo said. "Flow is very light out there today," he said. "I don't think many people want to do much ahead of the BOJ on Thursday." The Bank of Japan will hold a two-day policy meeting starting on April 3, its first under new Governor Haruhiko Kuroda, an advocate of aggressive monetary policy. A BOJ survey showed big manufacturers' mood improved after two straight quarters of deterioration, with the headline sentiment index rising 4 points to minus 8. That was roughly in line with a median market forecast of minus 7. The start of Japan's financial year also weighed on the market investors expected to book profits, traders said. All of the 33 sectors retreated across the board on Monday, with the index for land transport companies losing 4 percent, the worst performer. Financials also fell, with Mitsubishi UFJ Financial Group Inc losing 2.5 percent and Nomura Holdings Inc down 3 percent. However, index heavyweight Fast Retailing Co gained 1 percent, while TDK Corp and Tokyo Electron Ltd rose 2 percent and 1.4 percent, respectively. The broader Topix index ended the morning session 2 percent lower at 1,014.27.