What is が?
The particle が is one of the first particles you will encounter in Japanese, and it is also one of the most important. Its primary job is to mark the subject of a sentence. That is, it tells you who or what is doing something or existing in a particular state.
If you have studied は already, you might be wondering how が is different. And we have a detailed は vs が comparison if you want the full picture. Think of it this way: は highlights the topic: something already known or established in the conversation. が, on the other hand, points a spotlight at the subject itself. It says, "This right here is the one doing the action" or "This is the new piece of information."
For example, when someone asks "Who came?" the answer naturally uses が because you are identifying the subject as new information: 田中さんが来ました (Tanaka-san came). The focus is on who did it.
が also appears in specific grammatical patterns. You will always use が (not は) with adjectives of desire and ability such as 好き (like), 嫌い (dislike), 欲しい (want), わかる (understand), できる (be able to), and with existence verbs ある and いる. In these cases, the thing that is liked, wanted, understood, or existing is marked with が.
Another key role for が is inside subordinate clauses. The smaller sentences that sit inside a larger one. Even if the main topic uses は, the subject within a relative clause or a reason clause typically takes が.
Once you get comfortable with が, your Japanese will sound much more natural. Our lesson on basic sentence structure introduces が alongside は and も with plenty of practice. Let us look at how it works in practice.
When to Use が
1. Introducing new information or answering "who/what" questions
When you identify something for the first time in a conversation, or when you answer a question about who or what did something, use が.
2. After question words (だれ、何、どれ、どこ)
Question words like だれ (who), 何 (what), どこ (where), and どれ (which) always pair with が, not は. The answer mirrors the same structure.
3. With specific verbs and adjectives
Certain predicates require が to mark their object-like subject: 好き (like), 嫌い (dislike), 欲しい (want), わかる (understand), できる (can do), ある (exist, inanimate), いる (exist, animate), 上手 (skillful), 下手 (unskillful).
4. Inside subordinate clauses
When a clause modifies a noun or provides a reason/condition, the subject within that clause takes が rather than は.