～ものだ
used to / it’s how things are
～ものだ attaches to the plain form of a verb or adjective and steps back from one single event to comment on how things are in general. Depending on the form before it, it expresses a nostalgic “I used to...”, a general truth (“that's just how it is”), or a social expectation (“one is supposed to...”).
1. Nostalgic recollection: “used to”
With the past た-form, ～ものだ looks back fondly on something you did regularly in the past. It often appears with words like よく (often) or 昔 (long ago).
子供の頃はよく泳いだものだ。
“I used to swim a lot as a child.”
- 子供の頃（こどものころ）= childhood, when I was a child
- は = topic marker
- よく = often
- 泳いだものだ（およいだものだ）= used to swim
2. General truth: “that's just how it is”
With the non-past plain form, ～ものだ states something the speaker sees as part of the natural order of things.
人間は誰でも失敗するものだ。
“Everyone makes mistakes, that's just how people are.”
- 人間（にんげん）= human beings, people
- は = topic marker
- 誰でも（だれでも）= everyone, anyone
- 失敗するものだ（しっぱいするものだ）= make mistakes (by nature)
3. Social expectation: “one is supposed to”
～ものだ can also state what people in general ought to do like a shared social rule rather than advice aimed at one person.
年上の人には敬語を使うものだ。
“You're supposed to use polite language with older people.”
- 年上の人（としうえのひと）= older person
- には = to, toward (topic of the rule)
- 敬語（けいご）= polite language, honorifics
- を = object marker
- 使うものだ（つかうものだ）= are supposed to use
How to form it
Plain form + ものだ (for the nostalgic “used to” meaning, use the past た-form: V-た + ものだ)
- 泳ぐ（およぐ）= to swim → 泳いだものだ（およいだものだ）= used to swim
- 失敗する（しっぱいする）= to make a mistake → 失敗するものだ（しっぱいするものだ）= it's natural to make mistakes
- 使う（つかう）= to use → 使うものだ（つかうものだ）= one is supposed to use
Key idea
～ものだ zooms out from a single event to the general nature of things: what people commonly did in the past, what is simply true about the world, or what everyone is expected to do.
Built on the same stem
Updated .