Right knife radical - the indexing component. The image is of carving rules and divisions: 则 = knife marking out boundaries. Same radical anchors 划 (cut/draw), 利 (sharp/profit), 别 (separate), 刚 (firm).
Left 贝 once pictured a cowrie shell - early Chinese currency. Here it stands in for 鼎 (cauldron), the original left side, which carried laws and oaths inscribed on its body. 则 = a knife cutting rules into a sacred surface.
