青信号

1. Origins, structure, and basic meaning

• Structure: 青信号(あおしんごう) means the green traffic light indicating go.
• Basic usage: It is also used figuratively for a favorable judgment allowing a plan to proceed.

2. Common pitfalls and similar expressions

• A traffic light and a figurative go-ahead
  • 青信号になってから means after the light turned green, marking the sequence of actions.
  • 発売計画に青信号が出た figuratively means that the launch plan received the go-ahead.