Variant: Catan For Two
Catan for Two is an official two-player variation of Settlers, compatible with any variation. Unlike two-player variations in Catan spinoffs, Catan for Two introduces two neutral players, which expand whenever either player expands (with a road, settlement, or, in Cities and Knights, when a player builds or upgrades a knight). Catan for Two also introduces Trade Tokens, which may be used to perform special actions. Trade tokens are earned whenever a player builds near a desert or coastal hex, or by sacrificing a Knight card. Trade token actions cost two trade tokens for the leading player, and one for the trailing player.
Read more about this topic: Catan: Traders & Barbarians