Urban planning is a complex process that involves many different stakeholders and has a very long time frame. The United Nations' Declaration of the Rights of the Child states that children should be given the opportunity to express their views and that these should be respected. The complexity of the urban planning process poses challenges on how to involve children. This article presents Stadsbyggarna - a board game designed with the explicit goal to help children understand the nature of urban planning. It has been used in citizen dialog in the development of a new 30-year city plan in a mid-sized Swedish city. Nineteen school classes in the municipality have played the game. The result shows that the gameplay encourage urban planning discussions. Role-playing is identified as a key element of the game. The digital component initially planned to be included in the gameplay was however found to be superfluous.