The radical gen is easy to remember if you think of “magnet 磁” (cf. magnet 磁石 = じしゃく), where stones 石 are hanging at strings 糸 (simplified to 幺) [and fixed with a bracket 艹] behave mysteriously.
Vocabulary
率いる
ひきいる
to lead, to spearhead (a group), to command (troops)
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