Sekigahara is designed to offer an historically authentic experience within an intuitive game mechanic that can be played in one sitting. Great effort has been taken to preserve a clean game mechanism. (Despite a healthy amount of historical detail, the ruleset is a brief 6 pages.) Chance takes the form of uncertainty and not luck.
No dice are used; combat is decided with cards. Blocks = armies and cards = motivation. The combination of army and motivation produces impact on the battlefield. Armies without matching cards don't fight. Battles resolve quickly, but with suspense, tactical participation, and a wide range of possible outcomes.