防衛

1. Origins, structure, and basic meaning

• Structure: Written 防衛 and read ぼうえい, it means defending a place, country, or held position against challenge.
• Basic usage: It appears in fortifying a castle and in a champion retaining a title for the third time.

2. Common pitfalls and similar expressions

• Military defense versus title defense
  • In sport it figuratively means keeping a championship, not armed combat.