Reinforcement techniques with "Tanren-gata" Kenyu Mabuni & Kiyou Shimizu

There is a kata video that has been making the rounds on SNS of top kata runner Shimizu Kiyou.
It is not Chatanyara Kusanku or Suparinpei, which is her specialty, but "Naihanchi".
It is "Naihanchi. (bottom right image)
Master Kenyu Mabuni, the third generation Soke of Shitoryu, who also appears in the  video, teaches her the meaning of kata, traditional techniques, and practice systems that have been handed down to her since ancient times.
Most of them are called "Tanren-gata," such as "Naihanchi.