TOKYO, November 9, 2013 (AFP) - Oyama, who started the day with a one-shot lead, shot her second straight 68 at the Kintetsu Kashikojima Country Club to finish tied at 8-under 136 with Higa and Ichinose, who both shot 66s.
"I came this far so I'm definitely going for it tomorrow," the 36-year-old Oyama said. "My caddie this week caddied for Lee Bo-Mee, and she won last week so I think the luck is on my side."
Defending champion Stacy Lewis of the United States stayed within striking distance by shooting a 68 to sit three shots behind the leaders in the fifth and final stop on the US LPGA Tour's late-season Asian swing.
Last year, world No 3 Lewis came from seven shots back to win by one stroke on the final day of the tournament, co-sanctioned by the US and Japan tours.
"Yeah, it's kind of similar to last year when the first two days I just couldn't really drop many putts," said Lewis, who is aiming for her fourth title this season. "But hopefully tomorrow the gap kind of opens up a bit. But I've done it before, so I know it's possible."
The host nation is looking for its 10th title in the 41-year history of the tournament, and first since Momoko Ueda won the second of her two crowns in 2011.
By filling four of the top five spots, the prospects of a Japanese player taking home the $180,000 top prize were good.
Asako Fujimoto was tied with American Brittany Lincicome for fourth place at 7-under 137. Fujimoto shot a 67 while Lincicome, a five-time career winner with three top-10 finishes this season, had a 68.
Lincicome said that not playing in the final group means less pressure as she tries to end a two-year winless drought with a sixth career title.
"Not being in the last group, I think I play best or I've won the most from," said Lincicome, who was seventh in South Korea last month. "It will be fun to go out tomorrow. If I keep doing the same things I've done the last two days, it should be really close."
South Korean Chella Choi and Jang Eun-Bi both shot 69s and were another shot back in a tie for sixth place with Japan's Junko Omote (69) and Japan tour regular Teresa Lu (68) of Taiwan.
Japan's Yumiko Yoshida shot the low score of the day, a 7-under 65, to join Lewis at 5 under. Also in that group are Japan's Miki Saiki (66), American Julieta Granada (68) and South Korea's Hwang Ah-Reum (68).
Oyama, a 12-time winner on the Japan tour but winless this season, had a chance to remain in the sole lead, but had her lone bogey of the day on the par-4 15th hole.
The 20-year-old Higa, who has won twice in her first full season on the Japan tour, had six birdies in a bogeyless round, including three straight on Nos 14-16.
Like Oyama, Ichinose could have had the lone lead but had a late bogey, with hers coming on the par-3 17th hole. The 25-year-old had moved to the top of the leaderboard early in the round with a birdie spree, carding six over the first 10 holes, with four straight from the seventh to 10th holes.
"I really enjoyed today's round with Mamiko Higa, if she makes birdie then I make birdie, it was just like that all day," Ichinose said.
South Korea's Ryu Se Yeon, the world No 4, shot her second straight 71 and was in a large group in 22nd place at 2-under.
US LPGA Tour regular Mika Miyazato of Japan was another shot back after a 72.
Leading scores after the second round Saturday of the $1.2 million LPGA Mizuno Classic tournament at Kintetsu Kashikojima Country Club in Shima, Japan (Japanese unless stated):
Second round (par 72):
136: Mamiko Higa 70-66, Yuki Ichinose 70-66, Shiho Oyama 68-68
137: Asako Fujimoto 70-67, Brittany Lincicome (USA) 69-68
138: Teresa Lu (TPE) 70-68, Junko Omote 69-69, Chella Choi (KOR) 69-69, Jang Eun-Bi (KOR) 69-69
139: Stacy Lewis (USA) 71-68, Julieta Granada (PAR) 71-68, Hwang Ah-Reum (KOR) 71-68, Miki Saiki 73-66, Yumiko Yoshida 74-65
140: Brittany Lang (USA) 70-70, Austin Ernst (USA) 70-70, Gerina Piller (USA) 72-68, Lisa McCloskey (USA) 73-67, Ji Eun-Hee (KOR) 74-66, Rikako Morita 74-66, Han Hee-Won (KOR) 69-71
141: Natsuka Hori 72-69, Kumiko Kaneda 71-70, Rui Kitada 71-70, Lee Na-Ri (KOR) 69-72, Shin Ji-Yai (KOR) 69-72, Harukyo Nomura 72-69
Selected scores:
142: Ryu So Yeon (KOR) 71-71, Catriona Matthew (SCO) 71-71, Karrie Webb (AUS) 72-70, Park Hee Young (KOR) 75-67
143: Mika Miyazato 71-72, Feng Shan-Shan (CHN) 72-71,
145: Juli Inkster (USA) 76-69