The HSK (Hanyu Shuiping Kaoshi) is a standardized test for Mandarin proficiency, designed for non-native speakers. It consists of six levels, from HSK 1 (beginner) to HSK 6 (advanced). Each level includes listening, reading, and writing sections. Levels 1 and 2 don’t include writing, while Levels 3–6 test all three skills. HSK also has an optional speaking test (HSKK).