Japanese position words are nouns. You name the reference point first and join the position word to it with の: 机の上 is 'the top of the desk', that is, 'on the desk'. The order is the opposite of English and Vietnamese, where 'on' comes before 'the desk'. After the position word, you add a particle such as に or で, just as you do after any place noun.
§1Structure
Noun + の + position word (上, 下, 前, 後ろ, 中, 外, 隣, 間) + particle. The position word is a noun, so a particle follows it: に for existence (机の上にあります), で for the place of an action (駅の前で待ちます), は／が／です when the position itself is the subject (家の隣は公園です). 'Between A and B' is A と B の間. When the reference point is clear, 'Noun + の' can be left out (外で遊びます).
§2Examples
テーブルの上に花があります。
テーブルのうえにはながあります。
There are flowers on the table.
猫はいすの下にいます。
ねこはいすのしたにいます。
The cat is under the chair.
駅の前で友だちを待ちました。
えきのまえでともだちをまちました。
I waited for my friend in front of the station.
銀行は郵便局とスーパーの間にあります。
ぎんこうはゆうびんきょくとスーパーのあいだにあります。
The bank is between the post office and the supermarket.
かばんの中に何がありますか。
かばんのなかになにがありますか。
What is in the bag?
わたしの家の隣は公園です。
わたしのいえのとなりはこうえんです。
Next to my house is a park.
今日は寒いですから、外で遊びません。
きょうはさむいですから、そとであそびません。
It's cold today, so we won't play outside.
かぎはドアの後ろの箱の中にあるよ。
かぎはドアのうしろのはこのなかにあるよ。
The key is in the box behind the door.
§3Common mistakes
- Keeping the English or Vietnamese word order: ×上の机に本があります for 'There is a book on the desk.' The reference point comes first: 机の上に本があります. 上の机 is a different phrase and means 'the upper desk'.
- Leaving out の or the particle after the position word: ×かばん中に本があります, ×かばんの中本があります. Both are needed: かばん + の + 中 + に.
- Always using に after a position word: ×駅の前に友だちに会いました. に is for existence with あります／います (駅の前に銀行があります). When an action happens at that position, use で: 駅の前で友だちに会いました.
§4How it's different from similar grammar
- 隣 vs. 横 vs. 近く
- 隣 means 'next door' or 'the next one', and it is mostly used for two things of the same kind that stand side by side, such as houses, shops, seats and people: 銀行の隣に本屋があります (There is a bookshop next to the bank). 横 means 'beside' and can be used for any two things: 机の横にごみ箱があります (There is a trash can beside the desk). 近く means 'near' and the two things do not need to touch or stand in a line: 駅の近くにホテルがあります (There is a hotel near the station).
- まえに (before, in time)
- 前 is used for both place and time. After a place or a thing, 〜の前 means 'in front of': 学校の前にバス停があります (There is a bus stop in front of the school). After an event noun or the dictionary form of a verb, 〜まえに means 'before' in time: 食事の前に手を洗います, 寝るまえに本を読みます. 後ろ is different: it is only for place. For time, use あと: 食事のあとで.
§5How this shows up on the JLPT
In N5 Mondai 1, the blank is often the の before the position word (いす（ ）下) or the particle after it (に or で), so check the verb at the end: あります／います needs に, and an action verb needs で. In Mondai 2 (sentence ordering), keep 'Noun + の + position word + に' together as one block. Position words are very important in listening: you hear a sentence such as 本はテレビの横の箱の中にあります and choose the right picture. Practice following two position words in a row, from the big reference point to the small one.
§6Quick check (3 questions)
1. Choose the particle that fits the blank: 本屋は花屋＿＿隣にあります。
ほんやははなや＿＿となりにあります。
2. Which sentence correctly says 'The dog is under the bed'?
3. 郵便局は銀行とホテルの間にあります。 Which statement is true?
ゆうびんきょくはぎんこうとホテルのあいだにあります。