Heishu-kata & Kaishu-kata - Explained:

Heishu Kata means "kata with closed hands" or "fundamental kata". This kata teaches fundamentals (not only basics of movement but also principles) of the style while basics are learned during Kihon (Basic Movements). Traditionally, Kaishu Kata was taught as a second kata, or a "specialty kata" of a student, after Heishu kata, Sanchin-kata and/or Tensho-kata for Goju-Ryu is learned (this could take up to several years). Ranking (dan/kyu) and current kata curriculum with grading was established only after 1953, after Chojun Miyagi Sensei's death.

Kaishu Kata means a "kata with open hands" or "specialist kata". This is a more advanced from Heishu kata type. Kaishu kata serves as a "combat application reference" kata and is open to vast interpretation (Bunkai) of its movement's purpose (hence, "open hands").