Compound Particles in Japanese

In Brief

Japanese compound particles are fixed combinations such as において, に対して, について, によって, にとって, and をもとに. They connect a noun to the rest of a sentence and make relationships such as “in a setting,” “toward a target,” “about a topic,” “by a means,” “from someone’s viewpoint,” or “based on a source” explicit. They are especially common in news, academic prose, business communication, and formal presentations.

Overview

A particle is a short grammatical marker placed after a word or phrase. A compound particle (a multi-part expression functioning much like one particle) is longer than a basic particle such as は, が, を, or に. Many compound particles developed from an ordinary particle plus a verb or noun, but frequent combinations now behave as recognizable units: 会議において “at the conference,” 調査について “about the survey,” and 資料をもとに “based on the materials.”

At C1, knowing a rough English equivalent is not enough. The same English preposition can correspond to several Japanese forms, and one Japanese form can have several functions. For example, English by may indicate a method, a passive agent, or a deadline; によって covers the first two in suitable contexts, but not the deadline. The useful question is therefore not “What does this expression translate as?” but “What relationship does it establish?”

These expressions often sound compact, objective, and carefully structured. That makes them useful in formal writing, but it also means that overusing them in casual conversation can sound stiff. Their simpler equivalents remain important: において often corresponds to に or で, while について may correspond to a more conversational construction such as 〜のことを.

How It Works

The basic pattern is:

noun phrase + compound particle + predicate

A predicate is the part that says what happens or what is true, usually ending in a verb or adjective. In 研究について説明する, 研究 is the topic, について marks its relationship to the action, and 説明する is the predicate.

When the expression modifies a noun directly, it usually needs an attributive form—that is, a form placed before a noun. These forms are not all built in the same way, so learn each expression with its noun-modifying partner.

Main expression	Core relationship	Before a following noun	Typical plain alternative
N において	setting, place, time, field	N における N	N で / N に
N に対して	target, direction; contrast	N に対する N	N に; N とは違って
N について	topic	N についての N	N のことを / N の
N によって	means, cause, agent, variable	N による N	N で; N のため; N が
N にとって	viewpoint or affected party	N にとっての N	N には (sometimes)
N をもとに	source or basis used to create/judge	N をもとにした N / N をもとにする N	N から; N に基づく

において: the setting of an event or statement

において locates an event within a formal setting: a place, occasion, period, organization, or field. It commonly appears with conferences, research, history, law, education, and institutional activity.

• 会議において発表する — present at a conference
• 現代社会において重要だ — be important in contemporary society
• 教育における技術の役割 — the role of technology in education

For an ordinary physical action, で is normally more natural: 図書館で勉強した, not usually 図書館において勉強した. Choose において when the setting is being framed formally, not merely because English uses in or at.

に対して: directed toward, applied to, or contrasted with

に対して marks a target toward which an action, attitude, demand, or response is directed. It often follows people, groups, proposals, questions, and problems.

• 申請者に対して結果を通知する — notify applicants of the result
• 提案に対して反対する — object to a proposal
• 問題に対する対策 — measures addressing a problem

It can also set up a contrast, often with のに対して or a parallel pair: 兄が慎重なのに対して、弟は大胆だ “Whereas the older brother is cautious, the younger is bold.” Context distinguishes a target from a contrast.

Do not confuse this with について. 問題について話す means “talk about the problem”; 問題に対して行動する means “act in response to the problem.” One marks content, the other a target or point of engagement.

について: the topic under discussion

について introduces the subject matter of speech, thought, research, questions, or writing.

• 環境政策について調べる — investigate environmental policy
• 契約についての質問 — a question about the contract

With は or も, it becomes については or についても: この点については後で説明します “As for this point, I will explain it later.” The added は makes that topic contrastive or frames it for the next statement.

によって: means, cause, agent, or variation

によって has several established functions. Determine which one is present from the predicate and the wider sentence.

1. Means or method: オンライン会議によって時間を節約する — save time by means of online meetings.
2. Cause: 大雨によって試合が中止された — the match was cancelled because of heavy rain.
3. Agent in a passive sentence: この小説は夏目漱石によって書かれた — this novel was written by Natsume Sōseki.
4. Variation or dependence: 地域によって習慣が違う — customs differ depending on the region.

The noun-modifying form is による: 大雨による被害 “damage caused by heavy rain”; 地域による違い “differences by region.” For everyday tools and transport, で is often simpler and more natural: 電車で行く “go by train.”

にとって: evaluated from a viewpoint

にとって identifies the person, group, or entity for whom something has a particular value, difficulty, meaning, or importance.

• 学生にとって重要だ — important for students
• 私にとっての故郷 — the place that counts as home to me

It frequently occurs with evaluative words such as 重要だ, 必要だ, 難しい, 便利だ, 問題だ, and 意味がある. It does not normally mark the recipient of an action. “I gave a book to a student” is 学生に本をあげた, not 学生にとって本をあげた.

をもとに: using something as a basis

をもとに marks material, data, experience, testimony, or another source used to create, infer, design, or decide something.

• 統計をもとに計画を立てる — make a plan based on statistics
• 実話をもとにした映画 — a film based on a true story

Before a noun, をもとにした emphasizes the resulting product, while をもとにする describes a chosen method or policy: 利用者の意見をもとにする設計方針 “a design policy that takes user feedback as its basis.” The more formal に基づいて / に基づく often stresses conformity to evidence, rules, or an authoritative principle.

Examples in Context

Japanese	English	Note
会議において発表しました。	I presented at the conference.	Formal event setting
現代社会において、情報を見極める力が求められる。	In contemporary society, the ability to evaluate information is required.	Abstract setting
教育におけるAIの役割を検討する。	We will examine the role of AI in education.	における before a noun
この問題に対して、対策を考えます。	We will consider measures for this problem.	Problem as the target
会社は利用者の要望に対して迅速に対応した。	The company responded quickly to users’ requests.	Direction of a response
都市部では人口が増えているのに対して、農村部では減少している。	Whereas the population is growing in urban areas, it is declining in rural areas.	Contrast between clauses
新しい制度について担当者に質問した。	I asked the person in charge about the new system.	Topic of the question
その研究についての詳しい資料を送ってください。	Please send detailed materials about that research.	についての before a noun
この点については、意見が分かれている。	Opinions are divided on this point.	は highlights the topic
文化によって違います。	It differs depending on the culture.	Variation by category
大雪によって多くの便が欠航した。	Many flights were cancelled because of heavy snow.	Cause
この建物は著名な建築家によって設計された。	This building was designed by a famous architect.	Agent in a passive sentence
学生にとって重要なことです。	It is important for students.	Viewpoint of evaluation
海外で働くことは、彼女にとって大きな転機となった。	Working abroad became a major turning point for her.	Personal significance
調査結果をもとに、新しい方針を決定した。	We decided on a new policy based on the survey results.	Evidence used for a decision
このドラマは実際の事件をもとにしている。	This drama is based on a real incident.	Source material

Common Mistakes

Using において for every “in” or “at”

• Unnatural: カフェにおいて友達と話した。
• Natural: カフェで友達と話した。
• Why: A routine physical action normally takes で. において deliberately presents a place, period, or field as a formal setting.

Confusing a topic with a target

• Wrong for “We discussed the proposal”: 提案に対して話し合った。
• Right: 提案について話し合った。
• Why: Discussion has content, so について marks what the discussion is about. Use に対して when an attitude or action is directed toward the proposal: 提案に対して反対した.

Treating にとって as a recipient marker

• Wrong: 先生にとってメールを送りました。
• Right: 先生にメールを送りました。
• Why: に marks the recipient. にとって supplies a viewpoint for an evaluation: 先生にとって便利です “It is convenient for the teacher.”

Using によって for a deadline

• Wrong: 金曜日によって提出してください。
• Right: 金曜日までに提出してください。
• Why: English by hides several relationships. A deadline takes までに; によって marks such things as means, cause, passive agent, or variation.

Using the sentence-final form directly before a noun

• Wrong: 教育において問題
• Right: 教育における問題
• Why: Before a noun, において changes to における. Similarly, use に対する, による, and usually についての or にとっての.

Mixing up the basis and the resulting product

• Wrong: この映画をもとに実話を作った。 (if the intended meaning is “The film was based on a true story.”)
• Right: この映画は実話をもとに作られた。
• Why: The source or basis comes before をもとに. The new work or conclusion appears elsewhere in the sentence.

Usage Notes

Compound particles are prominent in formal genres because they label logical relationships clearly. Reports favor phrases such as 調査において, 結果について, and データをもとに; news reports frequently use による for causes and sources. In conversation, these forms are still possible, especially when the topic is serious or technical, but basic particles and verbs often sound more relaxed.

Punctuation does not belong to the particle itself. A comma after a long opening phrase can improve readability—この問題に対して、政府は…—but a short phrase does not require one. Avoid inserting commas mechanically after every compound particle.

Several forms readily combine with focus particles. については highlights or contrasts a topic; に対しても means “also toward/in response to”; においてのみ means “only in.” Keep the compound expression intact and attach は, も, or のみ after it.

English translation is especially unreliable here. に対して may become to, toward, against, in response to, or whereas. によって may become by, through, because of, or depending on. Translate the whole relationship and predicate rather than assigning one permanent English preposition to each form.

Beyond the Basics / Advanced Use

At an advanced level, closely related expressions differ in stance and register rather than in simple dictionary meaning.

Contrast	Practical distinction
において vs で	において frames an institutional, temporal, abstract, or rhetorically formal setting; で is the ordinary marker for where an action occurs.
に対して vs に	に対して makes the target relationship explicit and can sound more deliberate; に is often sufficient with verbs that already select a target, such as 答える.
について vs に関して	Both mark a topic. に関して is generally more formal and can suggest a defined matter or connection; について is neutral and very broad.
によって vs で	For means, によって foregrounds a method or causal mechanism; で commonly marks an everyday tool, medium, or transport.
によって vs のために	によって neutrally identifies a cause in many formal statements. のために often presents a reason and may be more natural when the consequence is unfavorable, though context matters.
をもとに vs に基づいて	をもとに presents source material used in creating or deciding; に基づいて more strongly suggests a judgment or action grounded in evidence, rules, standards, or authority.

Be careful with passive agents. によって is especially natural when authorship, invention, discovery, construction, or another historically identifiable act matters: 電話はベルによって発明された. In ordinary interpersonal passives, に is usually more natural: 私は先生に褒められた “I was praised by the teacher.” Using によって there would sound unnecessarily formal and detached.

The contrastive pattern A のに対して B links entire descriptions, not merely nouns. The の nominalizes the first description—that is, makes it function like a noun-like unit—so that に対して can establish the comparison. With nouns or な-adjectives, the forms reflect the grammar before の: 父が楽観的なのに対して、母は慎重だ.

Finally, formal writing often stacks relationships: 調査によって得られたデータをもとに、教育における課題について検討した “Based on data obtained through the survey, we examined issues in education.” Such sentences are grammatical, but clarity matters more than density. If several compound particles pile up, divide the sentence or replace one with a simpler construction.

Practice Tips

1. Sort by relationship, not translation. Make six headings—setting, target, topic, means/cause, viewpoint, and basis—and place new examples under the appropriate heading. This prevents the English words in, for, and by from controlling your choice.
2. Learn the paired forms aloud. Practice において → における, に対して → に対する, によって → による, and について → についての. Then build one full sentence and one noun phrase with each pair.
3. Rewrite for register. Take a formal sentence such as 会議において説明した and make it conversational: 会議で説明した. Then explain what changed in tone and whether the meaning stayed the same.

Related Concepts

• Prerequisite: Basic Particles は/が/を/に — the foundation for understanding how Japanese marks relationships between phrases.