The 20-year-old has been in fine form this season with victories in Ruka, Lake Placid, Calgary, Deer Valley and Sochi and he picked up another one in the first event as the tour moved to Japan.
Kingsbury, who claimed eight wins on the way to the moguls and overall freestyle ski World Cup titles last year, beat off fierce competition from three others in final two for victory.
Four of the final six were Canadian however it was Bradley Wilson in second place ahead of Olympic moguls champion Alexandre Bilodeau while Marc-Antoine Gagnon was fourth.
Kingsbury now has 705 points to his name at the top of the overall moguls World Cup standings, 192 ahead of second-placed Bilodeau with four rounds left this season.
It was a Canadian double in Inawashiro with Audrey Robichaud claiming her first victory of the season in the women's moguls event that took place before the men's.
Three Canadian's were in final two this time however again only one more was on the podium as Nikola Sudova of the Czech Republic beat Chloe Dufour-Lapointe into second.
Justine Dufour-Lapointe placed fourth and still leads the overall moguls World Cup standings with second placed Hannah Kearney not making it out of qualifying to rank 23rd.