Dungeons & Dragons Started as a Tweak to a Medieval Wargame

Gary Gygax and Jeff Perren published Chainmail in 1971, a rules system for tabletop battles between figurines representing medieval armies. It included an optional fantasy supplement that let you swap a unit of pikemen for, say, a wizard or a troll. Combat resolution used a 2d6 hit table and assumed each figure was a single soldier on a battlefield grid.

Dave Arneson, a Minneapolis wargamer, started running a campaign called Blackmoor that took Chainmail's fantasy bits and reduced the scale: instead of armies, each player controlled one character, exploring an underground dungeon. Players gained levels by surviving and looting. Arneson brought the system to Gygax in 1972; the two of them rewrote and expanded it over the next year.

In January 1974 Tactical Studies Rules — the company Gygax had set up in his basement in Lake Geneva, Wisconsin — printed 1,000 copies of the resulting boxed set. Gygax and his partner Don Kaye each put in $1,000 to cover printing. The set comprised three small saddle-stitched books: Men & Magic, Monsters & Treasure, and The Underworld & Wilderness Adventures. Gygax assembled the boxes by hand at his kitchen table, with friends and his children helping.

The initial run sold out in nine months. The combat rules in the original printing actually defaulted to Chainmail's 2d6 system; the now-familiar d20 "alternative combat system" was tucked into the text as a paragraph or two. By the third printing in 1975, it had become the default. The hobby that would put a 20-sided die into millions of basements over the next fifty years got its start as an option footnoted into a wargame supplement, sold a thousand boxes at a time.