Hybrid Format is an informal title for the phenomena of Western TCG duelists incorporating Japanese OCG cards into their decks, but still playing by TCG rules. Such duelists usually play by Traditional Format rules by default (as there is no Traditional Format in the OCG, and the Hybrid style of dueling itself is unofficial), and are mostly 'for fun' duelists (duelists who play the game as a social hobby and do not attend tournaments, where they cannot play such a format). Generally, the purpose of the Hybrid format is for TCG duelists to try out OCG-specific cards (those that haven't been released outside of the OCG), and see how they impact their own strategies, though this can be hard, as Hybrid duelists usually start out as TCG duelists and, therefore, do not know enough of the Japanese language to thoroughly know the effects, strategies, and rulings for the OCG cards they play. OCG cards are also comparatively easier and cheaper to get than their TCG equivalents, making hybrid dueling much easier to accomplish. Because of this kind of immersion into the realm of OCG, hybrid duelists tend to abandon the TCG altogether over time, as a better understanding of the OCG gameplay is acquired through hybrid dueling. This is also seen as a stepping stone to a duelist inventing their own rule set(s)
In the Philippines, there is a Metagame that follows this Format of gameplay, known as the 'Unsanctioned' or 'Advanced Open' tournament. This format allows for cards made both for OCG and TCG, and includes new cards not yet released in TCG, since Asia gains new Booster Packs earlier than TCG to allow highly flexible gameplay and to promote deeper understanding of rules and strategies limited by either OCG or TCG only formats.