Tanggeon is an inner hat made of horsehair or cow tail hair, which was worn by men before putting on gat (traditional hat). Men used to wear it when staying home. Tanggeonjang refers to the skill of making tanggeon, or to an artisan with such a skill.
Jejudo Island, where many horses were raised, was the main site for production of tanggeon. There are three types of tanggeon, depending on how they were woven, single-layer ones, double-layer ones, and those with square patterns. Tanggeon were made with square patterns for better appearance as they came to be used simply as hats.