首都圏

1. Origins, structure, and basic meaning

• Structure: 首都圏 combines 首都, capital city, with 圏, regional sphere, and refers to the capital and its surrounding region.
• Basic usage: Direction appears in 首都圏へ, while contrast with other areas appears in 首都圏と地方都市.

2. Common pitfalls and similar expressions

• Capital city versus capital region
  • 首都 is the central city, whereas 首都圏 extends to the connected surrounding area.
• Context-dependent boundary
  • The exact extent of the region can depend on context and should not automatically be equated with one administrative unit.