をもとに(して) — Based On
Indicates the source, material, or foundation on which something is created, judged, or done — 'based on', 'on the basis of', or 'using ... as a basis'. It marks the reference material that serves as the starting point. The form をもとにした modifies a following noun.
Structure
[Noun] + をもとに(して) ／ [Noun] + をもとにした + [Noun]
Examples
この映画は実話をもとに作られた。
Kono eiga wa jitsuwa o moto ni tsukurareta.
This film was made based on a true story.
実話 (true story) + をもとに marks the source material of the film.
アンケートの結果をもとにして、商品を改良した。
Ankeeto no kekka o moto ni shite, shouhin o kairyou shita.
We improved the product based on the survey results.
結果 (results) + をもとにして shows the basis for the improvement.
彼の体験をもとにした小説がベストセラーになった。
Kare no taiken o moto ni shita shousetsu ga besutoseraa ni natta.
A novel based on his experiences became a bestseller.
をもとにした modifies 小説 to mean 'a novel founded on his experiences'.
• Marks the raw material or reference that something is built upon. • をもとにした／をもとにする modifies a noun. • Register: neutral to formal; common with creating, judging, or revising.
Commonly confused with
The JLPT rarely asks whether you recognise a pattern — it asks which of several similar patterns fits. These are the ones をもとに(して) is tested against.
vs に基づいて
に基づいて (based on rules/principles) implies strict conformity to a standard, while をもとに treats the source as raw material that may be freely adapted.
vs を中心に
を中心に means an activity revolves around a focal point, whereas をもとに marks the material or source that something is built from.
More expressions
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