As I mentioned in a previous article, in my initial years of studying Japanese I made a huge emphasis on learning as much grammar as I could. For me, one of the most difficult elements of Japanese grammar is distinguishing between the particles は and が.
There are surely hundreds of books and websites that describe the basic usage of these, but a great majority of the explanations I’ve seen are incomplete and don’t have information to completely understand which of the two should be used in any given situation.
I think my confusion with these was further compounded by being self-taught, since I didn’t have a good teacher to get advice from. Moreover, if you ask a question like this to a native speaker (and I have on several occasions), odds are you won’t get a complete or easy to understand explanation. Just imagine trying to give a thorough explanation of English articles “the” and “a” to a non-native speaker. I’ve tried this also and believe me, it’s not easy.
Now that I’ve learned to distinguish these two a little better I thought I would share my experiences with others. First I’ll talk about the basics, which you may already know, and then go into the finer details.
The Japanese-101 explanation of these two is fairly simple, and goes as follows:
1) は describes the topic of a sentence (主題). You can think (roughly) of it translating to “As for X, …”. The word being described could also be the main subject, or just something that is being talked about.
As for Japanese, it’s difficult ==> Japanese is difficult.
2) が describes the subject of a sentence (主語). It describes who or what is doing an action, existing, or is in a certain state. が is commonly used when responding to a question, and が is also used after some question words (何、どれ).
What is in the garage? A car is in the garage.
Some learning resources will give a few more example sentence and leave it at this. This makes it difficult for non-native learners to properly understand and use these two particles, not only because there is no equivalent words in English, but also because there is a little bit more going on behind the scenes here. I’ll do my best to go into some of the nuances of these two particles to help clarify your understanding.
3) が can implicitly exclude other subjects.
Now, *I* am speaking now, so…. (implication for the other person to be quiet or listen closely).
Here the implication is that the speaker is talking, not anyone else.
が can be very difficult to translate because in English there is no simple word or expression to emphasize the subject. The only way I know to capture the feeling is via emphasis, as I did above with asterisks or by using tone of voice.
4) は can be used to express a comparison rather than just a topic.
Ex: 日本人が出る映画は 見ます。
(I) (do) watch movies which star Japanese people.
If this sentence was said in a discussion about different types of movies, it would imply that the speaker does watch movies with Japanese people, but doesn’t watch some other type of movie – namely, movies that do not star Japanese people.
は can also be used two or more times in a sentence to contrast things.
I like sports, but my brother doesn’t.
5) は is typically used to refer to a topic that was previously discussed in the conversation, or is assumed to be known by both parties.
The CEO said he quit the company.
Imagine seeing this sentence in the middle of an article about how the CEO had family problems that distracted him from his work. The は here is used to refer to a topic already known to the reader.
Replacing the は with が here is also possible, but sounds to me like someone else said that “社長が会社を辞める”.
On a related topic, sometimes in a novel I have seen where a character is first introduced using a “が” to describe their action, and then later は is used to describe a subsequent action. Once the reader already knows the character there is no reason to use が unless there is some doubt about who did said action, or if the author wants to emphasize that *that* character did the action, not someone else.
6) Frequently が is used within a clause that is used as a part of larger sentence.
I saw the dog run away.
I’ve added brackets above to show where the clause is, but usually you wouldn’t use those in writing.
Changing the 犬が to 犬は here would result in a very awkward sentence.
7) When used in a sentence without a question word, が confirms the subject, whereas は asks something about the topic.
I) Person A: 首になった
II) Person B: きみが？
III) Person A: 違う、けいこさんが 首になったらしい。
IV) Person B: 山本さんは？
In line II, person B is confirming their interpretation that Person A got fired. This could be translated as “you did?”. Notice that が is used by Person A in line III, since the focus is on who got fired (けいこさん）。
In contrast, the は in line IV is asking about 山本さん, which can be translated as “So what about Yamamto san?”. In other words, “What happened to Yamamoto san?”.
8) While が emphasizes the subject, は usually indicates that what is after the subject (the action, state, or whatever) is what is more important.
Imagine that you walk into a party and are looking for your friend, 松田さん。 To ask someone whether he is at the party, you could use the following expression.
Is Matsuda san here?
Here, the most important thing is not the Matsuda san himself, it’s the fact whether he is at the party or not. If the person you are asking is familiar with Matsuda san then you would be bringing up a topic already familiar to the other party (see #5 above).
Now imagine while you are searching for your friend, you see your teacher at the party. This surprises you and you think to yourself:
My teacher is here ！
Here the emphasis is on the teacher himself, since his presence is a big surprise.
Like other parts of Japanese that don’t directly correlate 1-to-1 to something in English, its best not to focus on the English translations. Rather, try to use the points I mentioned above to understand the general ways these two particles are used, and keep things in your head in Japanese (without translating to English) as much as possible.
Even assuming you memorize all the above guidelines, it will still take some time until you convert you academic, logical understanding into a natural intuition that works instantaneously. Although native Japanese speakers will naturally use は and が all day long without being consciously aware of it, in rare cases I have heard someone correct themselves in the middle of a sentence.
Creating a full formal definition of は and が is something that even Japanese scholars can debate about, so take your time learning them and don’t get too frustrated. I find it helps to occasionally stop myself when reading native text and think “Why was が ( or は) used here?”.
I used dictionary.goo.ne.jp as the main resource for this post. Some of what I said above is taken from the が／は／も article on that site, written in Japanese (See here). For advanced students I recommend taking a look at the detailed explanations and examples on this page.
Here is another site in Japanese that discusses the basics of these two particles in (somewhat difficult) Japanese.