HSK 5 is the threshold of fluency. 1,300 more words, formal vocabulary, idiomatic expressions, and the kind of register you'd hear on Chinese news broadcasts. Most heritage-speaker kids in serious immersion programs reach this level by middle school.
Practicing flashcards once won't stick. Bóyǎ schedules each word for spaced repetition so you review it exactly when you're about to forget. Available on Bóyǎ School.
Start studying free →HSK 5 maps to roughly CEFR B2/C1 and adds about 1300 words. It builds directly on HSK 4 (mandarin you'd actually need in a Chinese-speaking workplace.), so work through that first if you haven't.
The fastest route through this list is spaced repetition: Bóyǎ schedules every word for the moment you are about to forget it rather than re-drilling words you already know. Tones are taught explicitly on every card, and each session ends with you producing the language out loud, not just recognising it.
HSK 5 is organised around 4 themes: Idioms, Formal register, News & media, Long-form reading. Studying by theme keeps related words together so they reinforce each other.