Ni vs De: Location, Destination, Time, and Means

Compare the sentences

います locates a person; 勉強します locates an activity. Do not extend the shortcut “あります always takes に” to events: 会議室で会議があります means a meeting takes place in the meeting room. Also distinguish バスで行きます (travel by bus) from バスに乗ります (board a bus).

Compare the same place with different predicates

The English translation uses “at” in the first two sentences, but Japanese distinguishes the person's location from the place where studying happens.

に with あります and います

Use に for the location of a thing, person, or animal in these basic existence patterns:

• 机の上に本があります。 — There is a book on the desk.
• 部屋に猫がいます。 — There is a cat in the room.
• 田中さんは学校にいます。 — Tanaka is at school.

あります is the basic choice for things such as a book; います is used for people and animals. See あります and います for a fuller comparison.

Be careful with English “is.” A sentence identifying a place, such as ここは学校です (“This place is a school”), has a different structure. You do not add に or で merely because the English translation contains “is.”

に for a destination

With movement verbs such as 行きます, 来ます, and 帰ります, に can mark the destination:

• 学校に行きます。 — I go to school.
• 友だちが家に来ます。 — A friend comes to my home.
• 六時に家に帰ります。 — I return home at six.

In the last example, the first に marks a time and the second marks a destination. The same particle can have more than one role in a sentence.

へ can also mark direction with movement verbs. Compare に and へ after you understand the basic destination pattern.

で for the setting of an activity

Use で when a place tells you where an activity or event takes place:

• カフェで本を読みます。 — I read a book at a café.
• 公園で遊びます。 — I play in the park.
• 駅で友だちに会います。 — I meet a friend at the station.

In the last sentence, 駅で locates the meeting. 友だちに marks the person you meet. This is another reason to look at the whole sentence instead of treating に as a general translation of “at.”

The shortcut “あります always takes に” is also too broad. For a scheduled event, 会議室で会議があります (“There is a meeting in the conference room”) uses で for the event setting. Compare that with 会議室に机があります (“There is a desk in the conference room”), which locates a physical object.

で for a means or tool

で can describe how you do something:

Compare バスに乗ります (“I get on a bus”) with バスで行きます (“I go by bus”). に is part of the pattern for boarding; で presents the bus as a means of travel. Both can refer to the same journey from different perspectives.

に for a specific time

に often follows a specific clock time or date:

• 七時に起きます。 — I get up at seven.
• 月曜日に勉強します。 — I study on Monday.

Relative expressions such as 今日, 明日, and 毎朝 normally do not need the time particle に: 明日、勉強します (“I will study tomorrow”). Some time expressions allow choices depending on context, so do not turn this into a rule that every time word must take に.

Common corrections

These corrections assume the ordinary meanings shown in the first column. A different predicate or situation can give a place phrase a different role.

Apply both particles in one description

学校に行って、学校で勉強します。 — I go to school and study there. The first place is the destination; the second is the setting of an activity. A sentence can contain both particles without contradiction. Try the daily routine exercise and explain each place phrase before choosing its particle.

Practice: choose the function first

1. “I read a book at home”: 家（に・で）本を読みます。

2. “My friend is at school”: 友だちは学校（に・で）います。

3. “I go to Kyoto by train”: 電車（に・で）京都（に・で）行きます。

4. “I wake up at seven”: 七時（に・で）起きます。

5. “There is a meeting in the conference room”: 会議室（に・で）会議があります。

6. “I get on a bus”: バス（に・で）乗ります。

7. ‘I write with a pencil’: えんぴつ（に・で）書きます。

8. ‘I study tomorrow’: 明日（に・で・no particle）勉強します。 Choose the ordinary neutral form.