There were a number of posts over at B/X Blackrazor, which I've been reading since the announcement of the author's B/X Companion, that culminated in this entry. Something about it was percolating in the back of my mind; I think it became solid as I was reading back over about Braunstein, the wargame scenario that led directly to the development of Blackmoor and from it Dungeons & Dragons. This will be the first of a short series of posts on how I define D&D.
For me, at the core of D&D is a hidden-map game. The dungeon is the hidden map; in the course of the game, the map becomes known and the characters find the things marked on its key - whether that means monsters, treasure, traps, puzzles, or anything else the referee has chosen to put on it. To me this emphasizes the fact that the exploration is the heart of D&D, and any game worthy of the name focuses on this.
The hidden-map game is not just one mode of play in D&D. It is the subject of a relatively simple set of rules: characters have well defined movement rates, there are rules about the rate of exploration, opening doors, listening at doors, setting off traps, finding secret doors, running into wandering monsters. There are a number of internal timers built into the game, including the time needed to search, various upkeep items (rations, torches etc), the break every 6th turn, and of course random encounters. And if you play OD&D, Holmes Basic D&D, first edition AD&D, B/X D&D, and as far as I know Rules Cyclopedia D&D, and you follow the dungeon exploration rules, you will be playing basically the same hidden-map game as any of these editions. Later games branded as Dungeons & Dragons didn't have this; they subsumed the hidden-map game into a larger "game system."
From the perspective of actual play, this simple set of mechanics was at the center of a very light game engine. Other systems were developed for things like fighting monsters, determining treasure, casting magic spells and so forth - but in the early days of gaming these were not front and center. This is sharply differentiated from 3rd and 4th edition Dungeons & Dragons. 3rd edition was not about exploring the hidden map to find what was on it (and whether you'd survive), as much as it was a character-building game in which the DM provided combat-based "challenges" to the carefully crafted PCs. 4th edition is a tactical combat game at heart.
I bring this up first because, to me, the hidden-map game is the most fun part of D&D. I love drawing up maps of dungeons, with tricks and traps and twisting corridors and secret doors, and then having players progressively find their way through them, fighting or running, or tapping a 10-foot pole, and I also enjoy being on the other side of the table. It's a very evocative kind of fun and completely different from what you do in the modern games - and, to be honest, it's a game where combat is not the preferred option in most situations. It's unprofitable unless there's a mass of treasure to be had.
What I am not doing here is limiting what I think D&D is or does to the hidden map game. But that's the first major part of what D&D means to me. I'll post the second part later.