* Superlong JGBs underperform ahead of 30-yr debt sale Thurs
* Some exporters up as yen falls to lowest since May 2009 vs dlr
* Shares in real estate firms tumble as investors cash in gains
By Dominic Lau and Lisa Twaronite
TOKYO, April 9 (Reuters) - Japan's Nikkei average ended flat on Tuesday after rising to its highest level in nearly five years, as investors cashed in gains on stocks that had stellar performances after the central bank unveiled massive stimulus moves last week to revive the economy.
Japanese government debt prices eased, with longer maturities underperforming ahead of a 30-year sale later this week, even though the Bank of Japan lost no time in kickstarting the sweeping changes.
"There is some profit-taking after some of the big moves yesterday... Small real estate stocks are still getting up there," said a senior equity trader at a foreign brokerage in Tokyo. "It's still a quantitative easing market."
The real estate sector, which is seen as the biggest beneficiary of Japan's push to reflate the economy, sank 4.1 percent after rallying more than 26 percent during the previous three sessions.
Within the sector, real estate investment fund Kenedix Inc added 2.8 percent and was the most-traded stock on the main board by turnover.
The Nikkei was flat at 13,192.35 after trading as high as 13,331.39, its highest level since August 2008.
Financial firms, another sector expected to do well due to easing, also succumbed to profit-taking.
Lender Mitsubishi UFJ Financial Group dropped 2.5 percent, consumer financing firm Aiful Corp eased 0.2 percent and Nomura Holdings, Japan's top brokerage, slipped 0.3 percent. They were the second to fourth-most traded stocks.
On April 4, the Bank of Japan promised to inject $1.4 trillion into the world's third-largest economy in less than two years by buying government bonds across the yield curve as well as riskier exchange-traded funds.
The BOJ on Monday launched its campaign by offering to buy 1 trillion yen ($10.3 billion) of JGBs with maturities of between five and 10 years, and 200 billion yen of bonds with maturities exceeding 10 years.
The extraordinary measures, aimed at ending nearly two decades of deflation and economic malaise, have triggered a wave of buying in Japanese equities.
The benchmark Nikkei has surged more than 52 percent since mid-November, when Shinzo Abe promised expansionist fiscal and monetary policies, dubbed "Abenomics", to revive Japan's economy during his election campaign. He was elected prime minister the following month.
Japanese government bond prices were weaker on Tuesday. The 10-year yield inched down 1 basis point to 0.530 percent, well above a record low of 0.315 percent hit the day after the BOJ's policy announcement.
But 10-year JGB futures ended the day 0.33 point higher at 144.67, below their record high of 146.41 marked on Friday but also well off a 10-month low of 143.10 hit during that volatile session.
Longer maturities underperformed, with some investors eyeing Thursday's 30-year auction as the first test of real demand in the new market order forged by the central bank's radical programme.
"We are still getting used to a market in which the central bank is the main player, so it's hard to predict how the auction will go," said a fixed-income fund manager at a Japanese trust bank.
The 20-year yield added 6.5 basis points to 1.290 percent and the 30-year yield rose 7 basis points to 1.380 percent, although they were still below the level they were trading a day before the BOJ announcement.
Royal Bank of Scotland recommended investors buy the 30-year debt when the yield rose above 1.40 percent.
"We view the 1.2 percent range as a fair level for the 30-year while the BOJ maintains the current policy of buying 800 billion yen from the 10-year-plus sector per month," it said.
"We expect the period of trading in a broad range of 0.95 to 1.45 percent with this level as the median lasting through October, when investors begin factoring in an end to these purchases."
MUCH IN PRICE?
Andrew Pease, chief investment strategist for Asia-Pacific at Russell Investments, said the stock market had already priced in a strong rise in company earnings this year.
"If you look at the price-to-book value, which is still below 1.5 times, you know Japan still has got some long-term value," Pease said.
"It's still probably OK, particularly to the extent that you know they are going to push the yen down. But most of the reflation rally, I would say, already happened."
Some exporters were buoyed by a softer yen, which fell as much as 0.3 percent on Tuesday to 99.67 to the dollar, its lowest level since May 2009.
Canon Inc, TDK Corp, Suzuki Motor Corp and camera-to-endoscope maker Olympus Corp rose between 2.1 and 4.3 percent.
Societe Generale highlighted a number of exporters, which it said are "super sensitive" to yen depreciation, including office equipment maker Ricoh Co Ltd, Olympus, heavy machine maker Mitsubishi Heavy Industries Ltd, Honda Motor Co and Canon.