a type of bamboo, bamboo shoots, dice
箘 centers on a specific type of bamboo and its edible shoots. The dice meaning is a separate, rare usage that does not clearly connect to the bamboo idea.
箘 combines 竹 (bamboo) with 囷, which likely contributes the sound. The character originally referred to a type of bamboo and its shoots. The dice meaning is a later, unrelated borrowing.
The top 竹 is bamboo, and the bottom 囷 looks like a storehouse. Picture a bamboo storehouse full of fresh bamboo shoots.
For キン, imagine a bamboo shoot shaped like a key: key -> キン, and it unlocks a storehouse of bamboo.
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