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沖縄剛柔館 is the martial arts style Okinawan Gojukan or Okinawan Goju-Kan.
The meaning is “Okinawa hardness [and] softness hall.”
沖縄 = Okinawa.
剛 = Hard, firm, or strong.
柔 = Soft, softness, flexible, supple, yielding, gentleness, or pliant.
館 = Hall, building, school room, or an alternate word for a dojo.