JGBs up, curve flattens as buyers come in after Fed

* JGB buyers tiptoe in as market takes Fed meeting in stride

* Investor buying prominent in superlongs, curve flattens

* 30-year Treasury bond auction next focus

TOKYO, Aug 13 - Japanese government bonds edged up on Thursday, with gains in superlong maturities flattening the curve, as buyers tiptoed into the market with the closely watched Federal Reserve meeting out of the way.

The JGB market's response to Wednesday's Fed meeting, considered the week's main event, was limited and opened the door for bids to emerge.

"It was an anticlimactic outcome. It appeared the Fed was trying to minimise shock to the markets," said Noriyuki Fukuda, a fixed-income strategist at Morgan Stanley.

Although the majority of U.S. primary dealers had braced for the Fed to end its government debt buying programme in September, the central bank extended the scheme to October while leaving the purchase amount unchanged at $300 billion.

"In hindsight the Fed could be seen to have taken an important step, but the market has taken the outcome in stride so far," said Katsutoshi Inadome, a fixed-income strategist at Mitsubishi UFJ Securities.

Buyers were most active in superlongs. Twenty- and 30-year yields declined as domestic life insurers and pension funds, which had been holding back until the Fed meeting, came out to buy, albeit in subdued trading.

September 10-year futures rose 0.03 point to 137.53 after dipping to 137.55 soon after the morning open in a knee-jerk response to the retreat by U.S. Treasuries the previous day.

Two- and five-year yields were unchanged at 0.265 percent and 0.720 percent respectively.

The benchmark 10-year yield dipped 1 basis point to 1.405 percent and the 20-year yield fell 3 basis points to 2.130 percent.

The 30-year yield dropped 3 basis points to 2.305 percent after hitting a 10-month high of 2.360 percent earlier in the week.

The two-year/20-year yield spread tightened by 3 basis points to 186.5 basis points, pulling back further from a four-year high of 191.5 basis points hit earlier in the week.

Focus remained on the United States even with the Fed meeting out the way, as JGB investors eye how the U.S. bond market handles a 30-year debt auction later in the day.

Market players said the recent steepening pressure on the JGB yield curve could be eased further if the U.S. market absorbs the sale smoothly.