Some of the most useful sentences you can build in Japanese say "as one thing gradually changes, another changes along with it." As you climb the mountain, it gets colder. As the economy develops, life gets richer. As you age, your memory fades. Japanese has a tight cluster of compound particles for exactly this correlated-change relationship: につれて, にしたがって, に伴って (にともなって), and とともに.
They are near-synonyms — which is why textbooks lump them together and why learners then can't tell them apart. The way to master them is not to memorize four glosses but to lock onto the one condition they all share: both sides must be processes, gradual and unfolding. "As A changes, B changes" — not "A happened, then B happened." Get that requirement into your bones and the rest is register and nuance. This page sorts the four, then shows the line that separates them from ordinary sequence words like 後で and と.
The one rule that governs all four: process on both sides
Every particle here demands gradual, correlated change on both sides of the sentence. The left side (before the particle) must be something that unfolds over time — climbing, aging, developing, time passing. The right side (the main clause) must also be a change, not a static state. If either side is a single instantaneous event or a fixed condition, the whole pattern breaks.
山を登るにつれて、だんだん寒くなってきた。
yama o noboru ni tsurete, dandan samuku natte kita
As I climbed the mountain, it gradually got colder.
Both halves move: 登る is an unfolding process, 寒くなってきた is an unfolding change. The だんだん ("gradually") could be added to almost any sentence in this family — that is the tell that you are in correlated-change territory.
につれて — the prototypical "as / in proportion to"
につれて is the most neutral, most broadly usable member — good in speech and writing alike. It attaches to a dictionary-form verb (登るにつれて) or a change-noun (成長につれて). Think "in step with."
年をとるにつれて、記憶力が落ちてきた。
toshi o toru ni tsurete, kiokuryoku ga ochite kita
As I've gotten older, my memory has declined.
時間がたつにつれて、傷の痛みは和らいでいった。
jikan ga tatsu ni tsurete, kizu no itami wa yawaraide itta
As time passed, the pain of the wound gradually eased.
都会の人口が増えるにつれて、家賃も上がっていった。
tokai no jinkō ga fueru ni tsurete, yachin mo agatte itta
As the city's population grew, rents rose along with it.
にしたがって — "as / in accordance with" (and its second life as "obey")
にしたがって has two related jobs. In the correlated-change sense it works much like につれて — "as A proceeds, B follows suit" — with a slightly more formal, orderly feel (the verb 従う means "follow, comply").
北へ進むにしたがって、景色がどんどん変わっていった。
kita e susumu ni shitagatte, keshiki ga dondon kawatte itta
As we headed north, the scenery kept changing.
時代の変化にしたがって、人々の価値観も変わっていく。
jidai no henka ni shitagatte, hitobito no kachikan mo kawatte iku
As the times change, people's values change too.
But にしたがって has a second, non-change meaning: "in accordance with / following (an instruction)." Here it means literally obeying a rule, an order, or a guide — and it overlaps with the "based-on / along" particles on the に基づいて・に沿って page.
医者の指示にしたがって、薬を飲んでいる。
isha no shiji ni shitagatte, kusuri o nondeiru
I'm taking the medicine in accordance with the doctor's instructions.
矢印にしたがって、まっすぐ進んでください。
yajirushi ni shitagatte, massugu susunde kudasai
Please follow the arrows and go straight ahead. (polite)
Context disambiguates easily: a process on both sides ("as A, B changes") is the correlated-change reading; a rule or guide with no change on the right side is the "obey" reading.
に伴って — "accompanying / along with" (formal, large-scale)
に伴って (formal variant: に伴い) literally means "accompanying" — B comes as a companion to A. It is the most formal and large-scale of the four, at home with social, economic, and natural developments in writing and news. It attaches to change-nouns (発展, 増加, 接近) or dictionary-form verbs.
経済の発展に伴って、人々の生活も豊かになった。
keizai no hatten ni tomonatte, hitobito no seikatsu mo yutaka ni natta
Along with economic development, people's lives grew richer too.
人口の増加に伴って、都市部では住宅が不足している。
jinkō no zōka ni tomonatte, toshibu de wa jūtaku ga fusoku shiteiru
Accompanying the population increase, housing is in short supply in urban areas.
台風の接近に伴い、多くの電車が運休となった。
taifū no sekkin ni tomonai, ōku no densha ga unkyū to natta
With the approach of the typhoon, many trains were suspended. (formal)
に伴って carries weight. Use it for things a newspaper would report — development, growth, aging populations, approaching storms — and it will sound right; use it for "as my stomach got emptier" and it will sound absurdly grand.
とともに — "together with / as"
とともに means "together with," and in the correlated-change sense it says B unfolds in tandem with A. It is formal and written, and it doubles as a plain "together with" for companionship (家族とともに暮らす, "live together with family"), so context tells you which reading applies.
経験を積むとともに、少しずつ自信がついてきた。
keiken o tsumu to tomo ni, sukoshi zutsu jishin ga tsuite kita
As I gained experience, I gradually grew more confident.
気温の上昇とともに、桜が一斉に咲き始めた。
kion no jōshō to tomo ni, sakura ga issei ni sakihajimeta
As the temperature rose, the cherry blossoms all began to bloom at once.
Quick register/nuance map
| Particle | Feel | Best for |
|---|---|---|
| につれて | neutral, everyday | any gradual correlation, speech or writing |
| にしたがって | orderly, a bit formal | correlated change; also "in accordance with / obey" |
| に伴って / に伴い | formal, weighty | large-scale social, economic, natural change |
| とともに | formal, written | correlated change; also "together with" |
The boundary: correlated change vs sequence
This is where English speakers slip. English "as" is ambiguous — it covers gradual correlation ("as I climbed") and simple timing ("as I opened the door"). Japanese does not. For a single instantaneous event that triggers another, you do not use this family at all — you use the と conditional for an automatic trigger, or 〜た後で for plain "after."
ドアを開けると、猫が飛び出してきた。
doa o akeru to, neko ga tobidashite kita
When I opened the door, the cat came leaping out. (single trigger — と, not につれて)
大学を卒業した後で、東京の会社に就職した。
daigaku o sotsugyō shita ato de, Tōkyō no kaisha ni shūshoku shita
After graduating from university, I got a job at a Tokyo company. (sequence — 後で, not につれて)
Opening a door and graduating are point events, not gradual processes, so につれて would be wrong for both.
Common Mistakes
1. Using につれて for a one-time, instantaneous event. These particles need a gradual process; a single trigger takes と.
❌ ドアを開けるにつれて、猫が飛び出してきた。
doa o akeru ni tsurete, neko ga tobidashite kita
Wrong — opening a door is a single event, not a gradual process; use と.
✅ ドアを開けると、猫が飛び出してきた。
doa o akeru to, neko ga tobidashite kita
When I opened the door, the cat came leaping out.
2. Using につれて where you just mean "after." A point-in-time sequence needs 〜た後で, not a change particle.
❌ 卒業するにつれて、就職した。
sotsugyō suru ni tsurete, shūshoku shita
Wrong — graduating is a point event; for 'after graduating' use 卒業した後で.
✅ 卒業した後で、就職した。
sotsugyō shita ato de, shūshoku shita
After graduating, I got a job.
3. A static main clause instead of a change. The right side must also move; "as A changes, B is a doctor" makes no sense.
❌ 年をとるにつれて、彼は医者だ。
toshi o toru ni tsurete, kare wa isha da
Broken — the main clause must be a change, not a fixed state.
✅ 年をとるにつれて、体が弱くなってきた。
toshi o toru ni tsurete, karada ga yowaku natte kita
As one ages, the body grows weaker.
4. Using formal に伴って for a small, personal change. に伴って is for large-scale developments; a trivial bodily change wants につれて or と.
❌ お腹がすくに伴って、機嫌が悪くなった。
onaka ga suku ni tomonatte, kigen ga waruku natta
Register clash — に伴って is too grand for 'as I got hungrier'; use につれて.
✅ お腹がすくにつれて、機嫌が悪くなってきた。
onaka ga suku ni tsurete, kigen ga waruku natte kita
As I got hungrier, my mood got worse.
Key Takeaways
- All four — につれて, にしたがって, に伴って, とともに — express correlated gradual change: as A changes, B changes with it.
- The governing rule: a process on both sides. Never use them for a single instantaneous event (→ と) or plain sequence (→ 後で).
- につれて is the neutral default; にしたがって is orderly and also means "in accordance with / obey"; に伴って is formal and large-scale; とともに is formal and also means "together with."
- The main clause must itself be a change, not a static state.
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Start learning Japanese→Related Topics
- に比べて・に反して・にしては: Compared To, Contrary ToN3 — Three ways to hold two things up against each other — neutral comparison (に比べて), a reversal of expectation (に反して), and an evaluation that deviates from a benchmark (にしては).
- に基づいて・に沿って・に合わせて: Based On, Along, MatchingN3 — Three flavors of 'according to' that English collapses into one — grounding on a basis (に基づいて), following a line or policy (に沿って), and adjusting to fit a target (に合わせて).
- と: Natural ConsequenceN4 — The conditional と for automatic, inevitable, and habitual results — directions, machines, and nature — and its signature ban on commands, requests, and intentions in the main clause.