To pass $N4$, you must significantly expand upon the skills you acquired at the $N5$ level.

1. Vocabulary

• Quantity: You need to know approximately $1,500$ to $2,000$ words. These words cover almost all simple topics in daily life (shopping, transportation, health, weather, hobbies, etc.).

2. Kanji

• Quantity: You must be able to recognize and understand around $300$ to $350$ Kanji. This is more than double the requirement for $N5$.
• Usage: At the $N4$ level, you should be able to understand Kanji found in signs for small shops, basic public notices, or simple newspaper headlines related to daily life.

3. Grammar

• $N4$ grammar teaches you how to express slightly more complex ideas than simple sentences. Key areas include:
  • Additional Verb Forms: Learning forms such as the 'Potential form' (can do), 'Tai form' (want to do), 'Giving and Receiving' verbs, and 'Permission/Prohibition' ($Te-mo ii$/$wa ikemasen$).
  • Connecting Sentences: Using various conjunctions and linking forms (like Toki, Nagara, Kedo) to create complex sentences.
  • Requests/Suggestions: Making polite requests (e.g., $Te-kudasai$) or giving advice ('It is better to do' - $Ta-hou ga ii$).
  • Formal vs. Informal Language: Understanding and using the Plain Form (casual forms) of verbs and adjectives, which are used when speaking with family or close friends.

4. Communication and Comprehension

• Listening: You should be able to understand everyday conversations spoken at a near-normal speed, even when the speakers interject their opinions or thoughts.
• Reading: You should be able to read and comprehend short letters, notices, emails, or short paragraphs from books that are related to daily living.

In Conclusion: Passing $N4$ generally means you can handle the basic necessities of daily life to live and work independently in Japan.