に details
に — the point something sits at, moves to, or is handed to
財布はかばんの中にありますよ。
saifu wa kaban no naka ni arimasu yo.
Your wallet is in the bag. neutral
来週、京都に行きます。
raishuu, kyouto ni ikimasu.
I'm going to Kyoto next week. neutral
Examples
where something is — ある, いる, 住[す]む, 置[お]く and other verbs of location take に for the place occupied
財布はかばんの中にありますよ。
saifu wa kaban no naka ni arimasu yo.
Your wallet is in the bag. neutral
あ、猫が屋根の上にいる。
a, neko ga yane no ue ni iru.
Oh — there's a cat on the roof. casual
where something goes — the destination of 行[い]く, 来[く]る, 入[はい]る, 着[つ]く and 乗[の]る
来週、京都に行きます。
raishuu, kyouto ni ikimasu.
I'm going to Kyoto next week. neutral
明日の十時に御社に伺います。
asu no juuji ni onsha ni ukagaimasu.
I'll call on your office at ten tomorrow. formal
when — に pins an event to a clock time or a calendar date
会議は月曜日の三時に始まります。
kaigi wa getsuyoubi no sanji ni hajimarimasu.
The meeting starts at three on Monday. neutral
明日、六時に駅でね。
ashita, rokuji ni eki de ne.
Six o'clock at the station tomorrow, then. casual
the other party — に marks who an action is aimed at, and with もらう, 借[か]りる and 習[なら]う the same に marks who it came from
先生にお礼のメールを送りました。
sensei ni orei no meeru o okurimashita.
I sent the teacher a thank-you email. neutral
この辞書は友だちに借りました。
kono jisho wa tomodachi ni karimashita.
I borrowed this dictionary from a friend. neutral
弟に自転車貸しちゃった。
otouto ni jitensha kashichatta.
I went and lent my brother my bike. casual
Formation
{N}にattaches to noun
Notes
are ordinary while the relative time words reject it — 明日, 今日 and
昨日 stand bare.
Related patterns
Similar
The verb picks, not the noun — に names where something IS or ends up (東京に住む, 机の上に置く), で where an action is carried out (東京で働く), so the same 東京 takes either depending on what follows it.
Interchangeable on a verb of motion or transfer — 京都へ行く and 京都に行く are both ordinary — because へ names the direction taken and に the point reached; where に names a point, a time or the second argument a verb requires, へ is out (三時に, 先生に会う, 家にいる), and even arrival leans に (駅に着く).
Motion verbs split the pair by role — を marks the ground crossed or left (橋を渡る, 電車を降りる), に the point reached or boarded (駅に着く, 電車に乗る) — and 会う, 触る and 似る reject を outright and take に instead, however transitive their English looks.
Lookalikes
The same 先生に changes role with the voice of the verb — 先生に頼みました is "I asked the teacher", 先生に頼まれました is "the teacher asked me"; only the れる/られる tail says which に you are reading.
Combines with
〜に行く is this に on a purpose rather than a place, and the slot before it takes either a ます-stem or an action noun (買いに行く, 買い物に行く) — a plain dictionary form there is out.