Hello All - I have Absolutely NO Experience in the Art of "Japanese Jiujitsu", or Brazillian Jiujitsu" Haven't seen any Japanese Jiujitsu methods executed to my knowledge

Have seen some Brazillian Jiujitsu, where they mostly try and get You on the Ground, for a Choke Hold, or a Submission Hold ect,.:hamme Now, Too clear the Air - I believe that Brazillian Jiujitsu Is A Very Good Martial Art, because it fits within the Modern World! Again, I know nothing of (JJJ)!
Question; What would be a Basic Defense method (technique)be for someone, that attacks with Multiple Fist Strikes, in Japanese, and Brazillian Jiujitsu?