Wikipedia
Osaifu-Keitai
, literally "Wallet Mobile", is the de facto standard mobile payment system in Japan. Osaifu-Keitai services include electronic money, identity card, loyalty card, fare collection of public transits (including railways, buses, and airplanes), or credit card.
The system was developed by NTT DoCoMo but the system is also supported by other mobile phone operators. It uses Sony's Mobile FeliCa ICs.