sphere · zone

1. Origins, structure, and basic meaning

• Structure: 圏 denotes an area or range; its on-reading is けん.
• Basic usage: 圏内(けんない) means within range, while 圏外(けんがい) means outside the range.

2. Common pitfalls and similar expressions

• Phone coverage and prize contention
  • If a phone 圏内に戻った, it returned to coverage; if it 圏外になった, it went out of coverage.
  • 入賞圏内 means a range of positions from which a prize placement can be expected. Moving up into that range means entering prize contention, which is distinct from having a final prize placement confirmed.