"I've lost some ground so I've got some work to do tomorrow."
After sharing the overnight lead with Australian's Matthew Griffin and Deyen Lawson, Tanihara broke out of a congested top group to head the pack by two shots, after carding nine under par 63 to be 17 under overall.
"Nine under I'm really pleased with," Tanihara said through a translator. "The fact there was no wind was really helpful. Tomorrow a lot of it will depend on the weather and if it's windy I could struggle to extend the score.
"I have had some wins in Japan but never had the opportunity to win overseas. It is a huge challenge but it would also be a huge achievement (to win). I would really like to see my name written on the trophy."
Michael Hendry is the next best Kiwi in a tie for 10th having made six under par 66 to be seven under overall.
The 36-year-old Aucklander dropped two shots on the 11th and 18th, but eight birdies - including four in a row early in the back nine - shot him up the leaderboard.
Hendry was pleased with his putting but knows further improvement is needed to make a legitimate charge in Sunday's final round.
"It was a really solid round," said Hendry. "There was a lot of good opportunities early that I missed and then I made a few putts coming in.
"Unfortunately that bogey at the end takes me one further back which is a little frustrating going into tomorrow, but hopefully I can make them up quick."
Meanwhile, tournament favourite Ryan Fox is a long way back after reaching three under par 69 to be four under overall, tied for 26th with fellow Kiwi Michael Long.
Further back, Manawatu rookie professional Joshua Munn is paired together in 32nd with day one leader Steven Jones at three under.