This article is EXTREMELY vague on the technology used, but a store in Kamikumamoto, Trial, has introduced an automatic pay system where shoppers can register, toss their stuff in the cart, and exit the store without going through the hassle of a line. I suppose it’s based on RFID chips, which are now down to a couple yen apiece, cheaper than paying a cashier, particularly in Japan’s labor-starved economy. Drop by and check it out - you can use the densha, which also has the same system for cashless payments. - William