In Japanese, “ha” (は) and “ga” (が) are both particles that are used to indicate the subject of a sentence.
The main difference between the two is that “ha” is used to indicate the topic of a sentence, while “ga” is used to indicate the subject of a sentence.
Another way to think about the difference between “ha” and “ga” is that “ha” is used to introduce a new topic, while “ga” is used to focus on a specific element within the topic. Consider “ha” being used to describe a “heading” or a topic on a page with many paragraphs and “ga” being used to signify something related to the topic, or in the context of a page, as a “subheading” when talking about the topic. You don’t need to repeat the “ha” topic for each consecutive sentence, the same way you wouldn’t repeat a main heading on a page multiple times.
For example, if you were talking about a dog, you might say “Inu wa kawaii desu” (犬は可愛いです), which means “The dog is cute.”
You could also think about “ha” being used to signify a topic change by saying something like “In terms of / with regards to …” such as “With regards to the dog, it’s cute.”
In this sentence, “ha” is used to indicate that the dog is the topic of the sentence.
On the other hand, if you wanted to say “The dog is running,” you would use “ga” instead of “ha,” like this: “Inu ga hashiru” (犬が走る).
In this case, “ga” is used to indicate that the dog is the subject of the sentence, and it is performing the action of running.
In general, “ha” is used to indicate the topic of a sentence, while “ga” is used to indicate the subject of a sentence.
These particles are important for understanding the structure of Japanese sentences and for correctly identifying the subject and topic of a sentence.