A Link (リンク, Rinku) is a term used in the Genso Suikoden Card Stories TCG. Links are what allow successive character cards to be played in the game.
Overview
There are nine link groups in the game, named in alphabetical order from A to I. They broadly represent a character's personal ties. Each non-Mastermind character card (a card from the Leader, Commoner, Craftman or Free types) has one or more of these links.
If there are no pre-existing links (i.e., when a mission card is first played) then only a Leader card can be deployed. Once a Leader card is played, only a card with at least one matching link is able to be deployed following it. This continues on, with the following card needed to match at least one of the combined links of the previous cards.
Collaborative characters tend to have high number of links, while powerful, authorative, or lone characters tend to have lower amounts of links.