Baseball is a popular ball game mainly divided into indoor and outdoor. indoor baseball is played in enclosed arenas, where games are played for short periods of time and on smaller fields, suitable for short-term entertainment. outdoor baseball is played on a spacious field, the game time is long, the rules are stricter, and more professional fields and equipment are required. baseball can also be divided into nine-man system and twelve-man system according to the number of players, suitable for different team sizes. whether it's indoors or outdoors, baseball is an exciting and challenging sport.