A "chance" is an event or a situation significant for making a decision in a complex environment. Since we organized a session of Chance Discovery in KES 2000, the basic theories attracted the interdisciplinary community of researchers from philosophy, sociology, artificial intelligence, finance, complex systems, medical science, etc. Even stronger reactions from companies lead to organizing the Chance Discovery Consortium in Japan, achieving big fruits of business. In this talk, the methods of chance discovery are presented. In summary, visual data mining methods developed for chance discovery aid user's individual thoughts and users' group discussions about scenarios in the future. This process is called Double Helix, where humans and computers cooperatively make spiral deepening of their concerns with chances. In this process, valuable scenarios emerge with users' awareness of chances, like creatures emerging with the chromosome - crossing at crossover poin...