に沿って【にそって】

The grammar pattern に沿って (にそって) means "along", "in accordance with", or "in line with". It is formed from the verb そう沿う (そう, "to follow along / to go along") in its て-form, attached to a noun via the particle に.

It has two main usages:

Physical "along"

に沿って can describe movement or position along a physical path, line, or feature such as a road, river, or coastline.

Abstract "in accordance with"

に沿って is also common to express acting in accordance with a plan, policy, guideline, wish, or expectation. In this sense it means "following" or "in line with."

Modifier forms: に沿った / に沿い

When modifying a noun directly, the past-tense form に沿った is used as a pre-noun modifier.

The more formal conjunctive form に沿い can also appear in written or formal contexts with the same meaning as に沿って.

Nuance

Compared to に従って (にしたがって), which emphasizes obedience or compliance, に沿って has a softer nuance of "going along with" or "following the general direction of" something, without necessarily implying strict adherence.