が (subject marker)

• Reading: が
• Romaji: ga
• Formation: Noun + が + Predicate

Meaning

A particle that marks the grammatical subject of a sentence. が identifies who or what performs an action or exists in a state, and is especially used when presenting new or emphasized information.

While both は and が can mark the subject of a sentence, they serve different functions. が highlights the subject as new, unknown, or contrasted information, answering 'who?' or 'what?' questions. It is required in subordinate clauses, with certain predicates like ある, いる, できる, わかる, 好き, and 欲しい, and when describing something being perceived. In neutral descriptions of events, が marks the subject performing the action. Overusing は where が is needed is a common learner mistake, particularly in existential and ability expressions.

Examples

1. 猫が庭で遊んでいる。 A cat is playing in the garden.
2. 誰が来ましたか。 Who came?
3. 雨が降り始めた。 It started raining.

Usage Guide

Context: spoken, written, everyday

Tone: descriptive

Do Say

• 犬が走っています。
• 日本語がわかりますか。
• あの店のラーメンが一番おいしい。
• 電車が来ましたよ。

Don't Say

• 私はピアノはできます。(Using は instead of が with できる for ability) → 私はピアノができます。
• 誰は電話しましたか。(Using は instead of が in a question word sentence) → 誰が電話しましたか。
• 外は雨は降っています。(Using は instead of が for a natural phenomenon being described) → 外は雨が降っています。

Origin & History

が originally functioned as a possessive particle in classical Japanese, similar to modern の. Its use as a subject marker developed during the Muromachi period and became dominant in the Edo period.

Cultural Context

Generation: All ages

Social background: Universal