Revolution of decentralized consensus began from Bitcoin. We see the future of the world. Although we Japan lost in internet revolution, we do try to gain no.1 in the world in blockchain revolution from Japan. c0ban [C0BAN] is named after Middle Ages Samurai coin called Koban. We think we have still lots of issues on blockchain, crypto currency, and decentralized algorithm. c0ban is the first challenge for us to spread the technology to the world. Though the project, we will be pleased if we could provide a trigger to people to feel the revolutionary world of decentralized consensus.