Miki Saiki stayed on course for her first win in three years after a 2-under 70 on Saturday preserved her slim advantage heading into the final round of the Itoen Ladies.
Saiki, runner up at the Japan Women's Open last month, offset a bogey on the fourth hole with three birdies at Great Island Club to reach 7-under 137, one stroke clear of South Korea's Lee Na Ri.
"I was a bit nervous but I managed to limit myself to one bogey and I think that perhaps shows that I have improved," said the 26-year-old, who has not won since claiming her first tour victory at the 2007 Fujisankei Ladies Classic.
Saiki bogeyed the final two holes in regulation and missed out on the title at this tournament in 2007 in three-way playoff against eventual winner Rui Kitada and Hiromi Mogi. The Hiroshima native admitted the emotional scars had still not healed.