Kaiser (German for emperor) is a political/business simulation set in 18th century Germany. Players take the role of nobles in the Holy Roman Empire and compete for the crown of the emperor.

One to nine players can play, beginning by entering their name and gender and being assigned a state in the empire. Gameplay then takes place in turns, each consisting of a number of consecutive screens. In the first screen, players can sell and buy grain and land. Grain is necessary to feed a noble's subjects. Bad weather can result in harvest losses, making it necessary to buy extra grain to prevent starvation. Providing more grain than necessary increases population growth and the state's reputation. Acquiring more land increases population and is necessary for economic growth. Following the trading screen is a statistics screen, displaying births and deaths, immigration and emigration as well as income and expenses.

The third screen allows control of income. Players can set taxes and tariffs and can determine how harshly the justice system works - setting it to a level that is too brutal might increase income in the short term but also lead to increased emigration. Another overview screen follows, displaying a player's lands and properties in detail.

The fifth screen allows for spending the turn's income. It is possible to buy marketplaces and grain mills (both of which increase income) as well as construct part of a palace or a cathedral (both of which have no direct use but are required to move into the highest levels of nobility). Each building option requires owning a certain amount of land. Constructing five marketplaces and three mills results in the creation of a city.