AEG also runs many official tournaments. These range from more elaborate tournaments run by local stores, to regional tournaments known as Kotei tournaments, to large tournaments at major events such as GenCon in Indianapolis, Indiana, in the USA, every August. For more information about major tournaments, check the official L5R product site, and also keep an eye on this site, the Imperial Assembly, where tournaments will be announced and their results posted.
Speaking of results, while winners of tournaments often walk away with cool prizes, such as game products and trophies, many of the best tournament prizes involve the players's affecting the story of L5R. Tournaments will often allow the winner to make a choice that affects the story--for example, the winner of a tournament may be allowed to name one of the Clans, that will go on to fight and defeat a powerful opponent of the Empire; this will be featured in the regular L5R fictions, and also be reflected in the game itself. Sometimes winners get to name cards coming in future expansions to the game, or choose to which Clan a particular card will belong--the story prize possibilities are many and varied!