The HSK Exam
HSK stands for Hanyu Shuiping Kaoshi - literally, Chinese Level Exam. It's taken mainly by foreigners who wish to have confirmation of their level of Chinese, either for their own interest, university entrance or job-hunting. Apparently it's also taken by Chinese nationals who do not speak Mandarin as a first language - presumably mostly those from ethnic minorities. I don't know how common this is.The exam is available at three different levels. The first one is known as 'jichu' - literally foundation. This is where you come if you have only studied very little Chinese. As I understand it this is a relatively new addition to the HSK stable and I don't know much about it. According to the literature, this is suitable for those with between 100 and 800 hours of formal Chinese study.
The next level is known as 'chu, zhong ji' - elementary and intermediate level. This sometimes causes confusion, as 'jichu' is occasionaly translated as elementary thus making people thing that there are two elementary exams. I think what happened is that the HSK administrators decided to try and increase the number of people taking their exams annually and rather than divide and expand the elementary and intermediate levels they snuck in a foundation level at the bottom. I think this was unfortunate - mixing the elementary and intermediate level makes the exam look very daunting for those at lower levels, and the stated range of 400 to 2000 study hours is really a lot wider than it should be.
The advanced - gaoji - exam is the only one to include speaking and writing components (the elementary and intermediate exam includes some writing of characters, but nothing substantial). It is recommended for those who've studied for over 3000 hours.
some comments
A quick look at the above information will show that there are both gaps and overlap in the HSK coverage. If you've studied between 400 and 800 hours you could consider taking either the foundation or elementary / intermediate exam. Meanwhile, there's a great big gap between 2000 and 3000 hours of study - equivalent to about a year of full-time study.I think the HSK is generally a very well-designed exam - I found that preparing for the elementary and intermediate exam improved my everyday listening and reading a great deal. The listening in particular requires you to master a lot of colloquial Chinese usage, while the style of the reading pieces are similar to those you will find in the notices and newspapers you come across everyday.
There are an increasing amount of good quality preparation materials for the HSK - but at the same time, there's also a fair amount of rubbish. One unfortunate habit of publishers is to print a 'comprehensive HSK course' which is actually just a bunch of sample exam papers with no guidance or explanation of answers. Another problem is that materials are very often in Chinese only - manageable for those at higher levels, but somewhat inconvienient for some. Still, it's all good practice. . .