Not only cars but trucks, forklifts and construction equipment are sold at the Arai Equipment Auction, specifically Arai Oyama.
There are 4 basic auction areas: Arai Auto Auction Sendai (north of Tokyo), Arai Auto Auction Oyama (outer Tokyo), Arai Auto Auction Bayside (Yokohama) and Arai Auction Fukuoka (Kyushu).
Arai Sendai … every Tuesday from 11am .. cars
Arai Oyama … Tuesday: construction equipment .. Thursday: regular passenger vehicles .. Saturday: vans and trucks
Arai Bayside … Tuesday: motorcycles .. Friday: regular passenger vehicles
Arai Fukuoka … Tuesday: motorcycles