は vs が: topic, subject, and what you want to say

01Start with the question behind the sentence

Imagine arriving at a language exchange. If you are introducing yourself, 私は学生です is a natural way to say something about yourself: “As for me, I am a student.” は, pronounced wa here, makes 私 the topic. The useful new information is what follows it. は does not simply mean “I,” and it is not a marker that every subject must take.

Now someone asks which person is the student. 私が学生です identifies you as that person. The facts may be similar, but the conversational job is different. This is why isolated fill-in-the-blank questions using only 私___学生です can be ambiguous without a situation.

02Noticing something new

If you spot a cat outside, 猫がいます introduces its presence. You are telling someone that a cat is there. Once the cat is part of the conversation, その猫はかわいいです can make that cat the topic and comment on it. “New information versus known information” is a helpful pattern here, but it is not a universal rule for every use of は and が.

03は can also create a contrast

In コーヒーは飲みますが、お酒は飲みません, coffee and alcohol are contrasted. Here は takes the place of the object marker を. That alone shows why “は is the subject marker” is not a reliable explanation. You are sorting what you do and do not drink into two topics.

Do not automatically add contrast to every translated sentence with は. Sometimes it is simply the neutral topic. Tone, surrounding sentences, and what the other person expects all affect the reading. At first, look for explicit pairs such as coffee versus tea, today versus tomorrow, or me versus my friend.

04Choose in context, then practice

Before choosing, ask: am I saying something about an established topic, answering “who or what?”, or contrasting two things? These questions are more useful than translating は and が into English. Some predicates also have characteristic patterns, such as 日本語が好きです; learn the whole expression rather than forcing it into an English verb structure.

YOUR TURN

Make the connection.

Read the situation before choosing. The reason matters as much as the answer.