Chainmail rules for medieval miniatures by Gary Gygax and Jeff Perren, 3rd ed printing by TSR, 1975 (first published by Don Lowry's Guidon Games in 1971), with Lowry's illustrations plus photos of early sand table games which originally used 40mm scale Elastolin and Starlux toy soldiers.
Combat in Dungeons & Dragons was developed around the d6 Chainmail rules, but the first 1974 D&D set also included an optional d20 system that became the more popular choice.













