empty
豁 centers on openness and emptiness: a wide, clear space or a state of being unobstructed. The given meaning "empty" fits this idea of a vast, unblocked expanse.
豁 combines 害 (harm, obstruction) with 谷 (valley), suggesting a valley that breaks through obstruction, leading to openness. The exact historical development is uncertain, but the component combination likely expresses the idea of a wide, clear space.
Imagine a harmful barrier (害) being split open by a deep valley (谷), leaving a vast empty space. The valley cuts through the obstruction, creating an open expanse.
For カツ, picture a cat (カツ) walking through a wide, empty valley. The cat's name "Katsu" echoes the reading, and the open space fits the kanji's meaning of emptiness.