Rune Pieces are essentially pieces of a rune that players can use for various purposes throughout the series. First introduced in Suikoden as a means to add more customization options in weapon upgrades, they were replaced by Weapon Runes in Suikoden II and the Sword of Magic Rune in Suikoden III. They reappeared in Suikoden IV, where they served a similar function, and Suikoden V, where they work completely differently.