The Royal Navy's Instructions for Tactical and Strategical Exercises, 1921 Essentially, a set of Wargaming rules for Officer Training using wooden ships (or Cardboard equivalents). Also includes the "Details of ships of the principal Naval Powers" Appendix. In simple terms, it is a set of rules for running naval wargames, used to examine strategic or tactical problems. However, it contains useful information on the capabilities of RN ships as well as then-current naval thinking.