Relative position nouns (locational nouns) that indicate where something is. To link them to a physical reference object, you attach the object with the particle の.
[Anchor Noun] + の + [Position Noun] + に + あります/います
ベッドの下に猫がいる。
Beddo no shita ni neko ga iru.
There is a cat under the bed.
ベッド (anchor) + の + 下 (under) + に (particle marking place of existence) + 猫がいる (a cat exists)
私の後ろに立たないで。
Watashi no ushiro ni tatanaide.
Don't stand behind me.
私 (me, as anchor) + の + 後ろ (behind) + に + 立たないで (don't stand, negative request)
テーブルの上にりんごがあります。
Teeburu no ue ni ringo ga arimasu.
There is an apple on the table.
テーブル (anchor) + の + 上 (top/on) + に + りんごがあります (an apple exists — inanimate, so あります)
• Core roster: 上 (top/above), 下 (under/below), 前 (front/before), 後ろ (behind/rear), 中 (inside), 外 (outside), 隣 (next to), 横 (beside). • Noun status: Japanese treats these strictly as NOUNS, not prepositions. You are literally saying "at the bed's underside," which is why the の particle is required to connect the anchor to the position word.
The JLPT rarely asks whether you recognise a pattern — it asks which of several similar patterns fits. These are the ones 上 is tested against.
With these position nouns you use に for simply existing there (机の上に本がある — a book is on the desk). Use で only when an action happens at that spot (机の上で書く — write on the desk).
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