"I'm really glad that I won the title in my first final here. It was a tough match, but both of us played our best," said Jiang.
"I just played patiently. That's the key to the victory. We know each other. I planned to change the pace when I am in a difficult situation.
"This victory is very important because the level of our teammates are almost the same. It's tougher to play against my teammate, much tougher than when I play against players from other countries," she added.
It was Jiang's first title this season.
For Wang, who became world number one in the new rankings issued on Thursday, it was a second straight final defeat at the Japan Open.
Source: AFP Global Edition