The second more popular system was the familiar cross-index level to the Armor class, roll 1d20, if equal to or higher than the number on the chart you hit. If you hit you do 1d6 damage, regardless of weapon. Characters to-hit bonus and hit points increased as they level. But NOT ...
Armor items are protective items worn by characters to improve their defenses. Armor items are classified as light armor, heavy armor, or shield. Equipping light armor or heavy armor, other than unenchanted cloth armor, improves a character's armor class