sworn friend; inseparable friend
A classical Chinese-derived expression for a friend so close one would risk one's life for them. Literary and somewhat formal; not used in casual modern conversation.
He and I are what you would call sworn friends.
The two who faced life and death together on the battlefield were truly inseparable friends.
Common word for a close friend; lacks the classical, life-risking connotation of 刎頸の友.
A sworn friend or ally, often used in political or military contexts; similar in weight but more modern and less literary than 刎頸の友.
Standard kanji spelling using 頸 (neck).
Variant using the simplified character 頚 for 頸.
From the Chinese historical story of Lian Po and Lin Xiangru, where they became friends willing to die for each other. The phrase literally means 'friend of the cut neck', symbolizing a bond so strong one would not hesitate to sacrifice one's life.