war ocs Operational Combat Series OCS Simulates campaign-level combat from 1900 to the mid-1950s. The series goal is to allow a sophisticated study of historical events while maintaining mechanical simplicity. Currently published by Multi-Man Publishing. Official Support Page. The OCS Depot one-stop site for current Living Rules, Errata and other content. Such as the excellent OCS 101 Learning Tools, and all the Series Rules & Charts.