I wrote last year about the various types of advances players can discover in the campaign version of Strategic Primer. (At least one category has been added since that post, for what it’s worth.) And later I wrote about the how and why of the rules governing the “people” side of things, the player’s workers and other “units.” Today I’ll explain some of the largely mechanical side of things.
In the first campaign, the fundamental concepts were units and fortresses. Then, borrowing the idea from games like Civilization: Call to Power, it added “improvements.” Units, fortresses, and tiles could be improved, generally by adding equipment. But because the initial cases were improvements that obviously could be made only to tiles, units, or fortresses (for instance roads, cleats, or hoardings, respectively), the category of “improvements” was split into three.
On the other hand, something like a catapult does equally well with a unit in the field or set up in a fixed position in a fortress; in fact, the only significant difference between a catapult unit and a catapult improvement is whether the equipment is assigned to the men, or the men to the equipment. As the number of advances in the database increased significantly (with the additional problems of managing prerequisites and preventing advances that had already been added from being added again), the existence of, say, a catapult as a “unit or fortress improvement” and as a standalone unit (repeated dozens of times over with different kinds of equipment, from Mauser rifles to javelins—though neither of those precise items ever came up) became a growing irritant.
More than a mere irritant was that as the rules became more formalized (as I moved to computer assistance, then started thinking about a computer game version) it became impossible for, say, a unit of sling-men that defeated a unit of longbowmen to pick up their longbows for their own use, since a unit of longbowmen was distinct and different from a unit improved with longbows. Similarly, a player couldn’t use his existing cannon units as prefinished parts of a ship whose design called for cannon “improvements.”
As I revised the design (at least twice) over the next decade or so, I came to where we are today. “Units” aren’t advances, but groupings of men and equipment. And those units, men, or equipment can be used as parts of larger units. The only difference between a unit of longbowmen and a unit of slingmen that has picked up bows somewhere is in their training and experience. But once the game progresses far enough, the player doesn’t have to even think about this. That’s the essence of what I call the “module system,” a system of abstractions so the player sees an intuitive, useful, but somewhat realistic picture no matter what level of commander he or she is.