Shiranna comes from everyday Japanese speech rather than a single famous scene, with shiran meaning I do not know in casual Kansai dialect, shortened and delivered with a blunt, unbothered edge. That everyday familiarity is why it travels so well online: it needs no translation to read as a shrug, and creators pair it with subtitles in English and other languages. Shared as a short reaction clip, it has become a handy shorthand for playing dumb, dodging a question, or admitting confusion without losing confidence.