～に沿って – Along… / in line with…

1. Basic structure

Preceding word type	Formation with ～に沿って	Structure example	Notes
Noun (N)	N + に沿って	川に沿って歩く	Meaning "along" (physical) or "in line with/following closely" (abstract)
Noun (N)	N + に沿い	方針に沿い実行する	Written/abbreviated form
Noun (N)	N + に沿う + N	目標に沿う計画	Attributive form modifying a noun
Noun (N)	N + に沿った + N	規定に沿った手続き	Nuance of "staying on course/within standards"

2. Main meanings & detailed analysis

～に沿って has two main layers of meaning:

Along (literal): go/move along a road, riverside, route, boundary.
In line with, following closely (figurative): carry out work in accordance with established policies, criteria, plans, guidelines, targets, avoiding deviation.
Emphasizes adherence to a "line/criterion," unlike 「に基づいて」 (emphasizes an objective basis) and 「に応じて」 (emphasizes flexible adjustment).

3. Example sentences

この道は海岸線に沿って伸びている。
This road extends along the coastline.
マニュアルに沿って対応してください。
Please respond in accordance with the manual.
カリキュラムに沿い授業を進める。
Proceed with the lessons in line with the curriculum.
会社の方針に沿った評価制度を導入した。
We introduced an evaluation system aligned with the company's policy.
川に沿う遊歩道が整備された。
A walkway along the river has been built.
予算に沿って計画を見直す。
Review the plan in line with the budget.

4. Usage & nuance

Used when you want to emphasize not deviating from guidelines/criteria/a path.
Common nouns: 方針, 規則, 規定, 目標, 計画, マニュアル, カリキュラム, 地図, 境界線, 川/道/線.
Suitable for manuals/procedures; in geographical descriptions it carries the literal "along" meaning.

5. Comparison, distinctions, and similar patterns

Pattern	Meaning	Key difference	Short example
～に沿って	Following closely/in line with; along	Emphasizes following a line/guideline/criterion	方針に沿って実施する
～に基づいて	Based on an objective basis	Emphasizes the "basis/source of evidence"	データに基づいて判断する
～に従って	According to orders/rules; co-varying	"Obey/follow" is stronger in terms of command	指示に従って動く
～に即して／に則して	In accordance with norms/standards	Similar meaning; emphasizes "conforming to standards"	実情に即して見直す
～に合わせて	Adjust to match	Emphasizes proactive adjustment	相手に合わせて話す

6. Additional notes

Visualization: draw "a line" and move along that line → 「に沿って」.
In quality processes, a common pair is: マニュアルに沿って（execution）＋記録に基づいて（proof）.
For place names/roads, you can use 「沿い（ぞい）」 instead, as in 名詞＋沿いの道.

7. Variations & fixed phrases

N + に沿って／に沿い／に沿うN／に沿ったN
方針に沿って進める, 規定に沿った手続き, カリキュラムに沿い実施, 川に沿って走る
ご要望に沿ったご提案（a common service advertising phrase）

8. Common mistakes & JLPT traps

Confused with 「に基づいて」: if you need to emphasize a "scientific/data-based foundation," prefer 「に基づいて」.
Confused with 「に応じて」: 「に沿って」 does not express "changing flexibly depending on conditions".
Used with time-varying verbs like 「増える/減る」 to express co-variation → 「につれて／に従って」 is more natural.
Wrong part of speech attachment: what comes before 「に沿って」 is a noun.

Based On / Grounds