The European Go Federation adopted an Elo-based rating system initially pioneered by the Czech Go Federation. Despite questions of the appropriateness of using the Elo system to rate games in which luck is a factor, trading-card game manufacturers often use Elo ratings for their organized play efforts. The DCI (formerly Duelists' Convocation International) used Elo ratings for tournaments of "" and other Wizards of the Coast games. However, the DCI abandoned this system in 2012 in favour of a new cumulative system of "Planeswalker Points", chiefly because of the above-noted concern that Elo encourages highly rated players to avoid playing to "protect their rating". Pokémon USA uses the Elo system to rank its TCG organized play competitors. Prizes for the top players in various regions included holidays and world championships invites until the 2011–2012 season, where awards were based on a system of Championship Points, their rationale being the same as the DCI's for "Magic: The Gathering". Similarly, Decipher, Inc. used the Elo system for its ranked games such as "Star Trek Customizable Card Game" and "Star Wars Customizable Card Game". The Esports game "Overwatch", the basis of the unique Overwatch League professional sports organization, uses a derivative of the Elo system to rank competitive players with various adjustments made between competitive seasons. Leagues and match-makers for the skill-based game "" use Elo ratings such as ESEA League and Faceit; however, the game's own matchmaking system uses Glicko-2. Various online games use Elo ratings for player-versus-player rankings. Since 2005, "Golden Tee Live" has rated players based on the Elo system. New players start at 2100, with top players rating over 3000. In "Guild Wars", Elo ratings are used to record guild rating gained and lost through guild versus guild battles, which are two-team fights. The initial K-value was 30, but was changed to 5 in January 2007, then changed to 15 in July 2009. "World of Warcraft" formerly used the Elo rating system when teaming up and comparing Arena players, but now uses a system similar to Microsoft's TrueSkill. The MOBA game League of Legends used an Elo rating system prior to the second season of competitive play. The game "Puzzle Pirates" uses the Elo rating system to determine the standings in the various puzzles. "Roblox" introduced the Elo rating in 2010. The browser game "Quidditch Manager" uses the Elo rating to measure a team's performance.