Agent Marking: に vs によって | Japanese Grammar

English gets by with a single word — by — to name the doer of any passive: eaten by the dog, written by Dickens, destroyed by the flood. Japanese does not. Once you move past the everyday passive, you have to choose between two agent markers, に and によって, and the choice is not free variation. に is the workhorse of spoken, personal passives; によって is the marker of creation, discovery, and impersonal cause, and it dominates written and academic Japanese. This page shows you exactly where the line falls and, more usefully, why it falls there.

The default: に for everyday passives

For the ordinary passive — someone did something to you or to another person, and it affected them — the agent takes に. This is the passive you meet first, and it covers the vast majority of conversation.

また先生に叱られた。

mata sensei ni shikarareta

I got scolded by the teacher again.

満員電車で足を踏まれて、最悪だった。

man'in densha de ashi o fumarete, saiaku datta

Someone stepped on my foot on the packed train — the worst.

子供の頃、よく兄にいじめられていた。

kodomo no koro, yoku ani ni ijimerarete ita

When I was a kid, I often got picked on by my older brother.

Notice what these share: the subject is a person who is affected by the action. That is the natural home of に. It carries a faint sense that the action lands on someone — which is why the suffering passive (雨に降られた, "I got rained on") also uses に. に wants an animate, affectable subject and an agent that acts upon it.

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Think of に as the "it happened to me" marker. It presupposes someone on the receiving end who feels the consequences. Keep that image — it is exactly what makes に wrong for the sentences in the next section.

The switch: によって for creation, discovery, and cause

Now consider a different kind of sentence: This novel was written by Sōseki. Here the subject — the novel — was not affected by being written. It did not exist before the writing; the action brought it into being. There is nothing for the action to "land on" in the に sense. For exactly these verbs — verbs of creation, production, invention, and discovery — Japanese switches to によって.

この小説は夏目漱石によって書かれた。

kono shōsetsu wa Natsume Sōseki ni yotte kakareta

This novel was written by Natsume Sōseki.

電話はベルによって発明された。

denwa wa Beru ni yotte hatsumei sareta

The telephone was invented by Bell.

アメリカ大陸はコロンブスによって発見された。

Amerika tairiku wa Koronbusu ni yotte hakken sareta

The American continent was discovered by Columbus.

この会議は委員長によって開かれた。

kono kaigi wa iinchō ni yotte hirakareta

This meeting was convened by the committee chair.

The reason は/によって feels right here becomes obvious once you know what によって literally is: に + よって, the te-form of the verb 因る／依る (yoru), "to be due to, to depend on, to originate from." So によって literally means "owing to / by virtue of / originating from." It marks the source or cause from which the subject arose — not a party that suffered the action. That is a perfect fit for a created object.

The same logic extends to inanimate causes, where に is impossible because there is no animate doer at all:

地震によって多くの家が壊された。

jishin ni yotte ōku no ie ga kowasareta

Many houses were destroyed by the earthquake.

その問題は長い話し合いによって解決された。

sono mondai wa nagai hanashiai ni yotte kaiketsu sareta

That problem was resolved through long discussion.

An earthquake cannot "affect" a house in the に-passive's personal sense, and a discussion is not a person — so によって, "owing to / by means of," is the only natural choice.

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によって is not only a passive marker. Because it literally means "depending on," you will also meet it in non-passive sentences: 人によって考え方が違う ("ways of thinking differ from person to person"), 場合によっては ("depending on the case"). Same word, same core meaning — "as a function of X." The passive agent use is just one branch of that.

But に survives with "use," "love," "know"

Here is the trap. It is tempting to conclude "inanimate subject → によって," but that is wrong. A whole class of everyday passives keeps に even when the subject is inanimate and the agent is a vague crowd — verbs like 使う (use), 愛する (love), 知る (know), 話す (speak):

この橋は今でも多くの人に使われている。

kono hashi wa ima demo ōku no hito ni tsukawarete iru

This bridge is still used by many people today.

その歌は今も若い人に愛されている。

sono uta wa ima mo wakai hito ni aisarete iru

That song is still loved by young people.

彼の名前は世界中に知られている。

kare no namae wa sekaijū ni shirarete iru

His name is known all over the world.

Why do these resist によって? Because the subject is genuinely affected in an ongoing way — the bridge is subject to constant use, the song lives in people's affection. These are not one-shot creation events; they are continuous relationships between a doer and an affected thing, which is precisely に's territory. The dividing line, then, is not animacy. It is: did the action create/produce the subject (→ によって), or does it act upon an already-existing subject (→ に)?

Situation	Agent marker	Example
Person affected (everyday)	に	先生に叱られた
Creation / production	によって	漱石によって書かれた
Invention / discovery	によって	ベルによって発明された
Inanimate cause	によって	地震によって壊された
Ongoing use / love / knowledge	に	多くの人に使われている

Why writing defaults to によって

There is a second force at work: register. Even for a verb that could take either marker, formal and written Japanese leans hard toward によって, while conversation leans toward に. In a museum placard, a textbook, or a news report, によって sounds objective and appropriately detached; に in the same slot can sound too personal, as if the inanimate subject had feelings about what happened to it. Compare the everyday spoken version with the placard version of the same idea:

このお寺、昔の人が建てたんだって。

kono o-tera, mukashi no hito ga tateta n datte

They say people long ago built this temple.

この寺は8世紀に行基によって建てられた。

kono tera wa hasseiki ni Gyōki ni yotte taterareta

This temple was built by Gyōki in the 8th century.

The first is a casual active sentence you would actually say aloud; the second is the encyclopedic passive, with によって naming the historical creator. In genuinely formal or written prose you will also meet the contracted variant により (formal, written), which means the same thing:

本製品は当社の技術者により設計された。

honseihin wa tōsha no gijutsusha ni yori sekkei sareta

This product was designed by our company's engineers.

For the wider habit of dropping the doer entirely in this register, see agentless & inanimate passives and the formal written register.

A third marker: から for a source

For completeness: when the doer is the source of something that travels to the subject — praise, information, feelings, goods — から (formal-neutral) can replace に, emphasizing origin and direction:

みんなから愛されるキャラクターです。

minna kara aisareru kyarakutā desu

It's a character loved by everyone.

But から never works for a purely physical affliction: you can say 蚊に刺された but not ×蚊から刺された — a mosquito bite has no "source that sends something to you" reading. Treat から as an optional flavor of に, not a rival to によって.

Common mistakes

❌ この小説は漱石に書かれた。

kono shōsetsu wa Sōseki ni kakareta

Wrong register — に with a creation verb makes it read like the novel was somehow victimized by being written.

✅ この小説は漱石によって書かれた。

kono shōsetsu wa Sōseki ni yotte kakareta

This novel was written by Sōseki.

Using に with a creation verb is the single most common English-speaker error, because English "by" gives no warning. To a Japanese ear, 漱石に書かれた drags in the affected-subject nuance of に and hints that the writing was done to the novel's detriment — as if the poor novel suffered. Creation verbs need によって.

❌ この橋は多くの人によって使われている。

kono hashi wa ōku no hito ni yotte tsukawarete iru

Overformal / odd — ongoing everyday use takes に, not によって.

✅ この橋は多くの人に使われている。

kono hashi wa ōku no hito ni tsukawarete iru

This bridge is used by many people.

The mirror error: over-applying によって to a genuinely affected subject. 使う, 愛する, 知る describe ongoing action upon an existing thing, so they keep に even when the crowd of doers is large and vague.

❌ 家は地震に壊された。

ie wa jishin ni kowasareta

Wrong — an inanimate cause cannot take に.

✅ 家は地震によって壊された。

ie wa jishin ni yotte kowasareta

The house was destroyed by the earthquake.

An earthquake is not an animate affecter, so に has nothing to attach to. Impersonal causes always take によって (or により).

❌ 電話はベルに発明された。

denwa wa Beru ni hatsumei sareta

Wrong — invention is a creation event; に mis-frames it as affliction.

✅ 電話はベルによって発明された。

denwa wa Beru ni yotte hatsumei sareta

The telephone was invented by Bell.

Key takeaways

に = everyday agent, an animate doer acting upon an affected (usually animate) subject: 先生に叱られた.
によって = the doer or cause a created/discovered subject originated from; it literally means "owing to / depending on": 漱石によって書かれた, 地震によって壊された.
The real dividing line is creation vs. affliction, not animate vs. inanimate — which is why 使う・愛する・知る keep に even with inanimate subjects.
Formal and written Japanese defaults to によって / により (formal); conversation defaults to に or an active sentence.
から is an optional variant of に for a source (praise, info), never a substitute for によって.

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