leather tabi, Tungusic tribe
靺 centers on a specific type of leather footwear (tabi) and, by extension, a Tungusic tribe, likely through historical association with their distinctive leather boots or clothing.
靺 combines 革 (leather) with 末, which likely contributes a phonetic element. The character is historically associated with leather tabi and a Tungusic tribe, but the exact origin of the tribal association is uncertain.
Leather (革) at the end (末) of your legs: imagine traditional leather tabi boots covering your feet, with the leather extending to the very tips of your toes.
For マツ, picture a pair of leather tabi lying on a mat: mat -> マツ, and the leather boots rest on the woven surface.
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Mohe (one of the Tungusic-speaking tribes)