は
は
particle
topic marker
1.
topic marker
Marks the topic of a sentence—what the sentence is about. The topic is often (but not always) the grammatical subject. は sets up what the speaker wants to comment on, and the rest of the sentence provides information about that topic.
2.
contrast marker
Indicates contrast with something else, either stated or implied. When は is used on an element that would normally take a different particle (like を or に), it often adds a contrastive nuance: 'as for X (as opposed to something else)...'
は is pronounced 'wa' when used as a particle, not 'ha'. This is one of the most important particles in Japanese. The difference between は (topic) and が (subject) is one of the most challenging aspects for learners. Generally: は marks old/known information or the topic of discussion; が marks new information or identifies the subject when making a neutral description or answering 'who/what' questions.
Related Words
Contrast:
が (subject marker)