a type of bamboo, bamboo shoots, dice
箟 centers on a specific type of bamboo, including its shoots. The dice meaning is an unrelated, rare usage that does not connect to the bamboo idea.
箟 combines 竹 (bamboo) with 昆, which likely contributes the sound. The character originally referred to a type of bamboo.
The top 竹 is bamboo, and the bottom 昆 looks like a cluster of shoots with 日 as the sun above 比, two shoots side by side. Picture bamboo shoots growing under the sun.
For キン, imagine a king bamboo shoot: king -> キン, and the tallest shoot in the cluster is the king.
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