Knife
Radical
刂 dāo
禾 hé grain, cereal
The knife 刂
dāo that cuts the grain 禾 hé is sharp 利 lì
开 kāi open
Opening 开 kāi
the flesh or a wound with a knife 刂
dāo
is punishment 刑 xíng.
冈
gāng mountain
ridge
A knife 刂
dāo
as firm as a mountain ridge 冈
gāng is strong / indomitable 刚
gāng.
贝 bèi shell / shellfish
Having both the knife 刂
dāo and
the shell 贝 bèi (protection)
is a rule or regulation 则 zé.