Long ago BUNKAI was discussed

 

Kata Bunkai... Bunkai doesn't mean "application".

Bunkai means "analysis" or "disassembly" ('kai' kanji with 'on' pronunciation).
 

Kenwa Mabuni Sensei, founder of Shito Ryu, uses this term for the first time in written records in his 1934 book "Kobo Jizai Goshinjutsu Karate Kenpo”, "kata bunkai setsumei" (analysis and explaination).

 

Kenwa Mabuni and Chojun Miyagi were good friends and in the same book Mabuni appeals Miyagi "my senior", so we can assume Chojun Miyagi was aware of "bunkai" karate meaning.
In the essay "Ryukyu Kenpo Karatedo Enkaku Gaiyo", written and prepared by Chojun Miyagi on 28th January 1936, we can found:

“We untie Kaishu Kata which we already learned, and we study techniques of defense and offense in Kaishu Kata. Understanding its technical purpose, we practice the techniques of attack and defense (攻防の術 kōbō no jutsu) with fighting spirit like a real situation" (translation by Sanzinsoo).

The original Japanese for "untie" is "解き放ち" "Toki Hanachi" (to untie or to liberate): the first kanji in the same of 'kai', this time with 'kun' pronunciation.

"Understanding its technical purpose" is a key phrase and, in my opinion, we can use the fourth and the sixth precepts of Kenpo Hakku to better understanding.

We can find a short sequence of techniques, mae geri / hiji ate, more times in more kaishu kata but...

- (fourth precept) adapt to changing conditions (what's happened in the kata before and after the sequence, etc.)

- (sixth precept) distancing and postures dictates the outcome of the meeting (open or closed hands; control, deflaction, evasion, etc.)
(...to be continued)