What the Rules Leave Out is as Important as What is Written In

I've long consider that (i.e. the title above) one of the key insights in RPGs, and sadly a rare one to encounter. At least with any understanding.

The rules of a a game can be 100% concerned with combat and loot. And that tells you nothing about the campaign using those rules. The total time spent gaming might be 90% role-playing out political infighting with not a single die ever rolled or rulebook opened, with 10% of it spent actually in combat that results from someone losing politically.

All that a missing rule means is that the designer may will expect you to handle it on your own- not that it must be ignored. I attempted to cover this in my Layers of Design article back in 2002.

What brings it up today is that I get to look at the same subject from a slight different point of view.  That of a game designer trying to fit a set of core rules into a single 200 page book. Layers of Design looked at the sum total of all the rules, not just core rules or a single supplement.

Page limits impose a completely different reason for leaving stuff out. There's not room to put it in.

So instead of more than a dozen or so types of magic we use in our campaigns, there will only be five in the core rulebook. Just a handful of sample monsters instead of hundreds. Nothing about the campaigns we play. Nothing on mass combat. All those will have to wait for expansions, or just remain in the disjointed notes form they are now because I'm horrid at writing and really would rather just avoid it.

Some stuff isn't missing completely, but has been simplified. In place of pages of equipment lists and details is an abstract encumbrance and gear section taking up a couple of pages. It works, but leaves some gaps by its nature.

All of the man-to-man combat however is present. All the character generation except some missing classes.

After all this, I think in the end should someone unconnected to our campaigns read the resulting core rules (unlikely I know) in the end they'll end up not really know anything about our campaigns.