1.
breach, gap (in defenses)
A hole or opening broken through fortifications or enemy lines in military contexts.
敵陣に突破口を開く。
Open a breach in enemy lines.
軍は突破口から一気に攻め込んだ。
The army rushed in through the breach at once.
防御の突破口を探す。
Search for a gap in the defenses.
2.
breakthrough, opening, way out
A means of escape from a difficult situation; a key that opens up new possibilities.
突破口を見つける。
Find a breakthrough.
この技術が問題解決の突破口になるかもしれない。
This technology might be the breakthrough to solving the problem.
交渉の突破口を開くために、条件を緩めた。
I loosened the conditions to open a breakthrough in negotiations.
突破口 literally means 'breach opening' — a gap made by breaking through. Originally military, it is now commonly used figuratively for any breakthrough or way out of a difficult situation.
ETYMOLOGY:
突破 (breakthrough) + 口 (opening/mouth)
COMMON COLLOCATIONS:
- 突破口を開く: to open a breakthrough
- 突破口を見つける: to find a breakthrough
- 突破口になる: to become a breakthrough
- 突破口を探す: to search for a breakthrough
USAGE:
The figurative sense (sense 2) is far more common in everyday Japanese than the military sense. Often used in business, negotiations, and problem-solving contexts.