AD&D as a solo miniatures game

Just play Advanced Heroquest instead 

Solitaire D&D is a curious enigma. On the one hand, D&D is obviously a cooperative game for 3 or more players, one DM and at least two players. On the other hand, the early versions of D&D, and AD&D especially, were clearly tested solo. There is a wealth of content in the Dungeon Masters Guide for the solo gamer, buried deeply within its charts and tables and dice mechanics. The only thing the DMG does not provide is the story or plot of the game, but random dungeon crawling and wilderness travel does not require a story, and in fact in purist OSR circles random grid and hex encounters are considered the gold standard of play, and so is perfect for DM less play.

The first issue of The Strategic Review included a method for solitaire dungeon crawling and that method is copied and expanded in the first appendix of the DMG. Random dungeon generation, random generation of wilderness terrain and the attached random encounters and treasure rewards create all the content necessary for a game session. On top of that, the DMG has more tables for random town encounters, NPC generation, room contents, furnishing, unidentified potions and magic items, etc. All this random content may lead to weird and logically inconsistent results, and is sometimes frustrating for the solo player, but that is the result of lacking a dedicated DM.

The second best part of AD&D solitaire play is that nearly all the game systems have a dice mechanic attached. It's not the universal d20 system of 3.5 and 5e D&D, but it leads to more unique, context specific outcomes. To resolve the outcome of any action, a player simply has to pretend to be a DM for a moment and choose a proper mechanic and set of dice to roll, and let chance determine the outcome. Or not, and grant automatic success, no one will know, you're playing solo.  The amount of rules for the standard AD&D game is so vast, however, that it's possible to get through a whole game with just the given mechanics. This does restrict the kind of things you can do in the game however, and the really crazy imaginative out-of-the-box thinking that happens in regular group sessions doesn't really happen while following solo mechanics. Also in a live session the DM can determine success or failure without the need for dice, and generate content without needing tables.

The first time I played AD&D solo, I tried to stay close to "theater of the mind" style gameplay. Armed with nothing but character sheets, a notebook, graph paper, the rulebooks and some dice, I sat down to play the game, using the notebook as a journal and log. I did not really enjoy the experience, and it felt more like sitting down to do my taxes or take study notes rather than playing a game. Using miniatures and a battle map, however, greatly enhanced my enjoyment of the experience.  I now keep a large dry erase gridded battlemap as a general play space. On this map I keep small notes in the corner pertaining to the scenario I'm doing, and make ticks to mark off turns and rounds as an adventure clock. I keep miniatures in the marching formation and when it comes to the dungeon I only draw the rooms on the battle map in the event of an encounter or other situation that requires precise movement. Otherwise I draw the map of the dungeon on graph paper (the way a mapper in a live party should do), and only transfer the layout to my battle map in the event of an encounter. I then run the encounter as a tactical skirmish wargame, noting reaction checks and morale where appropriate, and then move on.

I like miniatures, I like visual maps, I like tactical wargaming, and I like writing quick notes on the board and erasing them rather than scratching everything out on notepaper. It made the game more visual and tactile for me, but it did result in more sprawl of game components. My character sheets, adventure clock, battlemap, miniatures, DM screen, notes and dice took up almost all of the dining room table to play. As a result, set up and teardown takes some time, and the components are not easily portable. And as I have young children, they cannot be left out for long. But these are the price to pay to play D&D on a personal, intermittent schedule.

While solitaire D&D play will never be as free wheeling and imaginative as a group session, it can approximate the fun and provide a unique experience in its own right, and the AD&D system provides a lot of content and mechanics to be used in service of this goal.