沖合

1. Origins, structure, and basic meaning

• Structure: 沖合(おきあい) refers to waters some distance out from the coast.
• Basic usage: It describes where a fishing boat heads after leaving harbor or the state of offshore waves.

2. Common pitfalls and similar expressions

• Position relative to the coast
  • 沿岸 focuses on an area along the coast, while 沖合 focuses on a location farther out to sea.
• Direction and location
  • 沖合へ向かう means heading offshore; 沖合で introduces something happening in those waters.