Tensū Arena is a tool for solo or group analysis of games and abstract positions. With its infinite branching mechanics, a set of graphic symbols, and a text commentary window, it allows you to replay and analyze any game situation, invent new combinations, and create game reviews, studies, and problems. Results are saved as sgf files, and importing these files allows you to load and view games played on various platforms. All of this is available in both solo and online group mode, where the training room creator can delegate control to any connected user. The program is downloaded to a PC (Windows) as an archive and launched using the executable file. An internet connection is required for working in group mode. Registration and authorization are not required.