The Swiss system is used for competitions in which there are too many entrants for a full round-robin (all-play-all) to be feasible, and eliminating any competitors before the end of the tournament is undesirable. In contrast, all-play-all is suitable if there is a small number of competitors; whereas a single-elimination (knockout) tournament rapidly reduces the number of competitors, but without proper seeding the best competitor may not necessarily win, as good competitors might have a bad day or eliminate and exhaust each other if they meet in early rounds.