Bunkai means “to break down”, and thus describes the whole process that lies in breaking down and understanding the application of the techniques in a Kata; we simply peel a Kata apart and take a closer look at the application of the individual techniques. The extracted techniques are called Ōyō.
Bunkai 分解: disassembly; dismantling; disaggregating; taking apart; breaking up; analysis; parsing
Ōyō 応用: Application
When we analyze the techniques of a Kata, we can see and maybe understand the use of these techniques in relation to self-defence. The easiest way is always to consider a Kata as it is. A block is a block (eg Age-uke) and an attack is an attack (eg Oi-zuki). This is a very simple way to interpret a Kata; this is also called Omote, which means “surface”. What you see is what you get! A kick is a kick and a punch is a punch, nothing else. The counterpart to Omote is Ura, which means “below the surface”, and this is where the real application of the technique can be found.
There are bunches of other Japanese words that can be used to describe the applications of the Kata; henka, honto, omote, ura are just some of them.
Some teachers like to use many Japanese words in their teachings, and it sounds really good and fancy, but it does not contribute to a better understanding for the student; using fancy words often creates more confusion around the topic than it benefits. Personally, I stick to the word Bunkai; well knowing that it is not entirely correct.
Thanks for reading