Prompted by the article (here) about kao there ensued a lively discussion on the internet as to whether kao should be translated as "to lean" or "to strike with the body". I want to summarize the discussion (in the hope that I represent the opinions of others to their satisfaction).
It all started with the note that kao should be translated correctly with "to lean".
In the New Chinese German Dictionary one finds about kao:
to ... lean, to lean on something, to approach, to come closer, to rely on
In the Great Chinese Dictionary (Zhongwen da cidian) Vol. 9, entry 43559, pp. 1616, one finds the following (thanks to Hermann Bohn):
There are three pronunciations: kao (4), ku (4) and gu (4)
to act against each other, to be based on each other, to make trouble - equivalent to gao (3)
In Mathews' Chinese English Dictionary:
To depend on, to trust to, to lean on, near to
Result: "To lean" can be found in dictionaries, but not "to strike with the body".
Is kao perhaps a technical term of Tai Chi Chuan?
In the Tai Chi Chuan of my teacher kao is clearly a strike with the body. It is an active strike with the shoulder, back or hip. It was confirmed to me, that this is also practiced by other teachers and in other styles as well. In the Classics kao is also described as a fast movement which can even be quiet violent. One can assume therefore, that kao is in this form a Tai Chi technical term.
However, other Tai Chi-players learned kao in a different way. Here I (the Tai Chi-player) "lean" on the vector of the incoming force, done fast or slow, high or low. This "leaning" can then be followed by a strike with the body.
Or I create/exploit the situation in which the opponent needs "to lean" on me - that is, that the opponent needs my shoulder/torso to support himself. If he depends now on this support and I take it away suddenly and use his static collapse for following techniques such as bringing him to the ground. In this case, kao is a special application of “let him fall into the emptiness.”
Kao was also described as the principle of leaning which has the strike with the body as an application. Here the 13 basic movements are generally understood as principles that manifest themselves in diverse techniques.
What is kao now? "To lean" or "to strike"?
I think, like so many other Tai Chi technical terms any translation is only a help. To keep kao simply untranslated would be best. But if it is translated, it has to match to the style and teacher. But looking outside the box, as here, can deepen one's knowledge tremendously.
As far as the discussion goes, I think it was very exciting and instructive: How the translation of a certain technical term can you make think about the contents of Tai Chi Chuan. I would like to thank all those involved.