Scales
鱗 uroko

Alternating triangles like snake or fish scales are a protective charm against evil; traditionally worn by women in their yakudoshi (unlucky) years.
Ancient talisman; crest of the Hōjō clan in the Kamakura period
Triangles were drawn in ancient tombs and on objects to ward off evil. In the Kamakura period the Hōjō regents took three triangles (mitsu-uroko) as their crest, and samurai wore scale patterns on armour and clothing as protection. In noh the scale pattern marks a woman turned serpent or demon, as in Dōjōji, and it was used on shrine decorations.
Still worn as a protective motif, traditionally in a woman's unlucky (yakudoshi) years.