Joshua is a grand strategy game set on the fictional semi-medieval continent of the same name. The people of Joshua are skilled in sciences and technology, which were used for good and evil purposes alike, leading to the invention of wondrous flying machines, but also mechanical war devices that allowed certain nations to take over large portions of the continent. The player can choose between any of the three scenarios, taking place during the fictional 10th to 12th centuries of Joshua's history. The earliest scenario puts the player in control of the small desert nation Rujua, in the middle one the ruler of the Principality of Ashumenia fights against the kingdom of Ishtakar, the final scenario takes place on a part of the continent occupied by the powerful Barm Empire, and the player must resist their invasion as the leader of the kingdom of Ans. The gameplay is similar to Koei's historical simulation games. Much of the interaction is menu-driven, as the player conducts interior policies, diplomacy, and military actions of the controlled state. As the ruler of a nation, the player has to keep the population happy, fortify cities, construct catapults for protection, train soldier, supply money and rations to the army, and engage in large-scale turn-based battles that take place on separate overhead screens.