We examine interoperability for integrated training simulation of a mechanized infantry battalion that uses a war game model of Korean army, Combat 21, and virtual simulators of K1 tanks. We discuss issues and problems for integrated simulation of the virtual and constructive models, including differences between the model scopes, model resolutions, engagement algorithms, and data consistency and training audiences of the war game model and virtual simulators. From these, we identify interoperability requirements. We propose ways of resolving the problems using a model converter.