nothing, not exist, crooked heaven radical (no.71)
无 centers on absence and negation: nothing, non-existence, or the concept of 'not'. The radical sense refers to a variant form of the 'crooked heaven' radical, which is used in characters related to lack or void.
无 is an ancient variant of 無, originally depicting a person with something covering or obscuring them, conveying absence or nothingness. The modern form is simplified and its exact pictographic origin is uncertain.
The shape looks like a person with their head tilted and arms crossed, as if signaling 'nothing here' or 'I have nothing'. The crossed strokes emphasize emptiness.
For ブ, imagine a boo sound when someone finds nothing: 'Boo, there's nothing here!' The boo sound cues ブ and reinforces the meaning of absence.