TOKYO, July 27 (Reuters) - Japanese government bonds were little changed on Monday despite a number of market-supportive factors such as sliding Tokyo shares, as investors were wary of chasing already low debt yields further down.

The benchmark 10-year JGB yield stood little changed at 0.405 percent. A move below 0.405 percent would take the yield to an eight-week low.

Ten-year September futures were slightly more responsive to factors like gains by German bunds, a weaker Nikkei and downbeat Chinese and European PMI data, rising 0.05 point to 147.54.

The two-year yield rose half a basis point to 0.005 percent ahead of Tuesday's auction of the maturity.

The finance ministry will sell 2.5 trillion yen ($20.25 billion) of two-year JGBs.

The market showed little reaction to the Bank of Japan's well anticipated move to buy 420 billion yen of JGBs. The central bank regularly purchases debt from the market as part of its extensive monetary easing scheme.

($1 = 123.4600 yen) (Reporting by Tokyo markets team; Editing by Jacqueline Wong)