last for making shoes, to turn on a lathe
楦 centers on shaping material on a form: a wooden last used for making shoes, and by extension the action of turning something on a lathe.
楦 combines 木 (wood) with 宣, which likely contributes the sound. The character refers to a wooden form or last used in shaping shoes or turning on a lathe.
The left side 木 is wood, and the right side 宣 looks like a roof over a sun. Imagine a wooden last (楦) under a workshop roof, used to shape shoes in the sunlight.
For ケン, picture Ken the shoemaker turning a wooden last on his lathe: Ken -> ケン, and the wood spins into shape.
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