Qijing Shisanpian (棋经十三篇) is an ancient Chinese work, The Classic of Weiqi in Thirteen Chapters.
The website of the FIGG hosts a translation in English (PDF format). (Bad Link)
This is really informative and elegant translation, though with few exception that I can't totally agree. So let me express some remark here in my broken English, and please correct me if I am wrong.
Chapter 12 was translated as
"There are nine mental levels into which players are distinguished. The first is called 'being in the spirit', the second 'seated in enlightenment', the third 'concreteness', the fourth 'understanding changes', the fifth 'applying wisdom', the sixth 'ability', the seventh 'strength', the eighth 'being quite inept', and the ninth and last 'being truly stupid'."
I don't think the eighth (zuo4 yu2 in Mandarin Chinese) and the ninth (sho3 juo2) should be translated into negative terms. These nine levels are for good players, so it can't be inept nor stupid.
zuo4 yu2 means 'seemingly stupid' literally. sho3 juo2 means 'protect one's weakness' literally. These are not bad terms. I guess these nine terms are all from some Taoist classics or other classics, but I am not sure their origin and implied meanings. Today zu4 shen2 juo4 jao4 (the first and second level) are still used to describe a person with great skill (not necessary skill of Go).
As far as I know originally the rank of Chinese Taipei Go Professionals were actually these nine levels instead of dan. And the Hankuk Kiwon uses these nine levels to describe dan players ( http://www.baduk.or.kr/information/info_player_ko.asp). See the kanji in the parentheses (two characters for each level). I think the eighth level and ninth level which are used to describe Korean 2 dan and shodan respectively should not be translated as inept/stupid.
I don't understand a word of Chinese, let alone ancient Chinese, but knowing a smattering of Japanese I was interested in seeing which characters were used for the terms. The obvious (to me) interpretations for them were amusing, so I collected the terms here along with translations (and some amusement).
- 1 dan: 守拙. Being truly stupid.
- 2 dan: 若愚. Being quite inept.
- 3 dan: 鬪力. Strength.
- 4 dan: 小巧. Ability.
- 5 dan: 用智. Applying wisdom.
- 6 dan: 通幽. Understanding changes.
- 7 dan: 具體. Concreteness.
- 8 dan: 坐照. Seated in enlightenment.
- 9 dan: 入神. Being in the spirit.
Next the amusement. These have been "translated" using modern Japanese meanings for the characters, stylized and commented for amusement value. It divides naturally into three substages.
- 1 dan: 守拙. Protective bungler. (you newcomer, you..)
- 2 dan: 若愚. Some foolishness. (finally had to be admitted he can do something)
- 3 dan: 鬪力. Fighting strength. (can't beat young newcomers in fighting, eh?)
- 4 dan: 小巧. A little cleverness. (starting to get old and sly)
- 5 dan: 用智. Using knowledge. (tricksy as a matter of course)
- 6 dan: 通幽. Versed in deep matters. (as wily a trickster as they come)
- 7 dan: 具體. Concrete understanding. (finally learns how not to lose even with honte)
- 8 dan: 坐照. In the light. (plays correctly and tries to make others see the Light)
- 9 dan: 入神. Beyond human. (has discovered a truly remarkable solution for which this life is too short for)