oak, mooring pole, used in proper names, (kokuji)
槝 is a Japan-made character (kokuji) that centers on a type of oak tree, with an extended sense of a mooring pole likely made from its wood. It also appears in proper names.
槝 is a kokuji (Japanese-made kanji) combining 木 (tree) with 島 (island), likely created to name a native oak species or a mooring pole associated with coastal areas. The exact historical origin is uncertain.
A tree (木) from an island (島) that provides strong wood for an oak mooring pole. Picture a sturdy oak on a small island, its trunk used to tie boats.
For かし, imagine a cash (かし) payment made with oak acorns on the island. The sound of 'cash' cues かし while the oak tree stands nearby.
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