TOKYO, Oct 24 (Reuters) - The benchmark 10-year Japanese government bond yield fell below 0.600 percent on Thursday for the first time since May 9, tracking overnight gains in U.S. Treasuries.

The 10-year yield dipped 0.5 basis point to 0.595 percent, while 10-year JGB futures rose 10 ticks to 145.01, their highest since early May.

JGB yields have been on a downtrend lately, helped this month by buying from Japanese investors including pension funds and life insurers. October is the start of the second half of Japan's fiscal year.