暗礁

1. Origins, structure, and basic meaning

• Structure: 暗礁, read あんしょう, means a submerged reef or an obstacle to progress.
• Basic usage: It is used for a reef a boat must avoid and for negotiations obstructed by a cost issue.
  • 小舟は海面下の暗礁を避けてゆっくり進んだ。

2. Common pitfalls and similar expressions

• 暗礁に乗り上げる
  • 暗礁に乗り上げる uses the image of a boat running onto a reef to describe work stalled by an obstacle. In the negotiation context, the cost-sharing issue is blocking progress.