“Signature” multiplayer games are played with decks built for Format3 (Trinity/F3T). It is designed to be played with 3 or more players, using almost all of the normal rules and gameplay from the official Pokemon TCG except for 3 New Rule Sets.
Games of “Signature” are best of 1 by nature, and are intended to be a casual way to play with 3 or more players. Unless it is explicitly stated below in the 3 special rules section, all other rules questions are directed to the current official rules for the game.
In Trinity format, every deck has a Signature Pokemon that you will start the game with. When constructing your deck, you may have up to 3 “Rule Box” cards, minimum of 1 (which is required to be a Basic “Rule Box” Pokemon, aka your “Signature” Pokemon). As normal, your deck must have exactly 60 cards, but in Trinity Format, you are restricted to using no more than 3 “Types”, I.e., “Electirc”, “Fighting”, “Grass”, “Psychic”, “Normal”, etc., and no more than 1 copy of any card other than Basic Energy (Singleton). For example, you can only have 1 copy of “Professor’s Research” or “Boss’s Orders” and only 1 copy of “Charmander” or “Charizard ex”. The restriction is based off of the Card Name itself, regardless of whether or not there are any differences between 2 cards that may share the same name. Finally, the legal card pool consists of cards from Black & White forward.
To begin the game each Player rolls 3d6, the high roll chooses who goes first, (with the turn order to proceed clockwise, as normal), Then each Player takes their “Signature Pokemon” and sets it aside before shuffling their deck and presenting for cut. After cuts, everyone places their “Signature Pokemon” face up on top of their deck and proceeds to draw 7 cards. Because of this Special Rule, there is no Mulligan in Format3.
Due to there being more than 2 players, the game is to be played in “rounds”. A round is completed once each player currently in the game has taken a turn during the current round. You are not allowed to target another player’s active or benched Pokemon for battle who has already been targeted for battle this “round” unless there are no other valid targets remaining in play. Also, if your active Pokemon is knocked out, you do not promote a benched Pokemon to the active spot until the end of the round, meaning that all players have taken their turn. Each player performs their own individual “Check-Up” phase immediately before their turn starts and immediately after their turn ends. Finally, you are also not allowed to pass your turn without attacking unless you are simply unable due to having no valid targets remaining in play or by having insufficient energy to perform an attack.