The defending Toray Pan Pacific Open champion earned one of the results of the season with her semi-final demolition of world number one Garbine Muguruza.
The Dane, who won the Tokyo title in 2016 and also 2010, put the Spaniard to the sword with a ruthless 6-2 6-0 victory.
The world number six has yet to get silverware in her hands despite reaching six finals already in 2017.
If that is to change she will have to beat Anastasia Pavlyuchenkova - a 7/4 chance with Sky Bet - who booked her third final of the year by ending Angelique Kerber's resurgence.
Kerber has had a dreadful year following a stellar 2016 but was looking good in Japan until her meeting with the Russian, who triumphed 6-0 6-7 (4/7) 6-4.
Elsewhere, Shuai Zhang won her second WTA title as she enjoyed home success in the Guangzhou Open.
Zhang, seeded second, had to battle hard to beat world number 65 Aleksandra Krunic, emerging a 6-2 3-6 6-2 victor.
Jelena Ostapenko is one win away from a first title since the French Open as she booked a spot in the final of the Korea Open.
The Latvian has been hit and miss since her maiden grand slam victory in June and needed three sets to get past Thailand's Luksika Kumkhum 3-6 6-1 6-1.
She will meet Brazil's Beatriz Haddad Maia, who got the better of Richel Hogenkamp 6-1 7-6 (9/7).
Ostapenko is the 2/5 favourite to win the final with her opponent at 2/1.
And British number two Heather Watson missed out on a place in the main draw of the Wuhan Open after losing in the final round of qualifying.
Watson was beaten 6-1 4-6 6-4 by world number 91 Ons Jabeur despite being a break up in the deciding set.
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