JLPT N2Spoken and writtenFilms, books, reports

をもとに（して）based on; made from

You take something as raw material and make something new from it: a film from a true story, a plan from survey results.

これは実じつ話わをもとにした小しょう説せつだが、人じん物ぶつ名めいや結けつ末まつは創そう作さくである。

This novel is based on a true story, but the characters' names and the ending are invented.

アンケートの結けっ果かをもとに、新あたらしい研けん修しゅうの内ない容ようを組くみ立たてた。

We put together the content of the new training program from the survey results.

How to form it

Noun + をもとに（して）

して is optional and changes nothing. Before a noun it is をもとにした: 日にっ記きをもとにした映えい画が, a film based on a diary. At the end of a sentence it is をもとにしている.

Before it: What you start from: 実じつ話わ, 経けい験けん, 記き憶おく, データ, 資し料りょう, 調ちょう査さの結けっ果か.
After it: Making something or working something out: 作つくる, 書かく, 計けい画かくを立たてる, 予よ測そくする.
Also written: を基もとに, を元もとに. The reading is the same.
Where you'll meet it: Film and book blurbs, news, reports. Fine in conversation too.

In use

この映えい画がは実じつ話わをもとにしているそうだ。

I hear this film is based on a true story.

過か去こ十じゅう年ねん間かんの気き象しょうデータをもとに、洪こう水ずいの発はっ生せい確かく率りつを予よ測そくした。

We predicted the probability of flooding using weather data from the past ten years.

古ふるい設せっ計けい図ずをもとにして、失うしなわれた門もんをCGで再さい現げんした。

Working from old plans, they recreated the lost gate in CG.

Two kinds of "based on"

English "based on" covers both of these.

これは事じ実じつをもとにした映えい画がです。

This is a film based on real events.

Real events were the material. Names and scenes may be invented.

これは事じ実じつに基もとづいた映えい画がです。

This is a film based on real events.

The film claims to stay close to what happened.

をもとに says what something started from. に基もとづいて says what it sticks to.

With data or survey results both are said, and either is right. に基もとづいて is the more formal of the two.

Close neighbours

に基もとづいてN2

What is decided or done rests on a rule, a standard or the facts, and sticks to them.

委い員いん会かいは、提てい出しゅつされた証しょう拠こに基もとづいて事じ故この原げん因いんを特とく定ていした。

The committee identified the cause of the accident based on the evidence submitted.

を頼たよりにN2

"Going by" a map, a memory or a faint light, usually with little else to rely on.

古ふるい地ち図ずを頼たよりに、霧きりの中なかを山やま小ご屋やまで歩あるいた。

Going by an old map, I walked through the fog to the mountain hut.

のもとで・のもとにN2

The same sound, but this もと is 下, "under": under a person's guidance, a system or an agreement.

新あたらしい校こう長ちょうのもとで、学がっ校こう改かい革かくが進すすんでいる。

School reforms are moving forward under the new principal.

Check yourself

1What does this tell you about the film?

この映えい画がは実じっ際さいの事じ件けんをもとにしている。

Choose an answer to see why.

2Which one fits?

これは、作さく者しゃの留りゅう学がく経けい験けん（　　）小しょう説せつです。

Choose an answer to see why.

More sentences

この映えい画がは祖そ父ふの日にっ記きをもとに作つくられた。

This film was made from my grandfather's diary.

子こ供どもの頃ころの記き憶おくをもとに、この曲きょくを書かいた。

I wrote this song from my childhood memories.

試し作さく品ひんをもとに、さらに軽けい量りょう化かした新しんモデルを設せっ計けいした。

Using the prototype as a starting point, we designed a new, even lighter model.

目もく撃げき者しゃの証しょう言げんをもとに、事じ故こ当とう時じの状じょう況きょうを再さい構こう成せいした。

They reconstructed what happened at the time of the accident from eyewitness accounts.

調ちょう査さの結けっ果かをもとに、来らい年ねんの計けい画かくを立たてた。

We drew up next year's plan from the survey results.

Compared with similar forms

Ways to say "based on"