who · what
topic — "as for …"
I'm a student. (as for me …)
subject · new information
Oh, there's a cat!
direct object — what the verb acts on
I drink water.
too · also — replaces は / が / を
I'll go too.
where · when
to (goal) · at (a time) · where something is
七時に起きます。
I get up at seven.
where an action happens · by means of
I study at the library.
toward — the direction of movement
I'm going to Japan.
from — a starting point in space or time
I came from Tokyo.
until · as far as — the end point
I walk to the station.
joining nouns
with · and (the complete list)
I watch a movie with a friend.
of · 's — links noun to noun
It's my book.
and … among others
I buy bread, milk and so on.
than — the thing compared against
I like cats more than dogs.
Spelling vs sound: as particles, は is read wa, へ is read e, を is read o.
easily confused
は vs が
Question words as the subject (誰が・何が) always take が, never は — and so does the answer: 田中さんが来ました。
に vs で
いる・ある・住む take に (東京に住んでいます); most action verbs take で.
に vs へ
With movement verbs they are interchangeable. Only に marks a time (七時に); only へ can take の: 母への手紙 — a letter to Mom.
と vs や
や often ends with など: パンや牛乳などを買いました。