Air, Earth, Fire, and Water Format is a Deck format used in some Pegasus Challenge tournaments. It is only run in Advanced Format. In this format, every player's Main Deck must include at least 4 EARTH, 4 FIRE, 4 WATER, and 4 WIND monsters. Air, Earth, Fire, and Water was the official Pegasus League format that started in November 2009, using the September 2009 Advanced Format Forbidden and Limited lists.