The answer, according to linguists and JLPT data, is roughly . This is the magic threshold where you move from "survival phrases" to near-fluent comprehension of news, anime, and daily conversation.

Review 20 new words per day. In 300 days, you will know 6,000 words. In 10 months, you will read a Japanese newspaper for the first time.

That is the power of the 6,000-word threshold. Now go find your PDF and start learning. Have you used a 6k PDF? Which version worked best for you? Let us know in the comments below. ganbatte!