The 'bitter/pungent' radical. Originally a pictograph of a tattooing knife used to mark criminals — extended to senses of punishment, hardship, and the sharp 'bitter' flavor. Indexes a small but evocative set: 辜 (crime), 辟 (open up / regal), 辨 (distinguish), 辩 (argue), 辫 (braid). Also surfaces as the eighth Heavenly Stem.