It was on the grid of the final race that Team Tsuchiya (#25) has decided no-tire-change strategy.
That's because they knew that rivals were the same strategy at that time.
But it isn't possible to exchange tire before the final race.
So Takeshi Tsuchiya made an air pressure of tire very low to keep tire wear well.
He struggled for the 1st stint because of this low air pressure.
But this choice is effective, and they finally have got a series champion.
http://motorz.jp/car/18529/