伝でん家かの宝ほう刀とう

expression, noun

last resort; trump card

Idiomatic expression referring to a final, decisive resource held in reserve for a critical moment. Often used in the phrase 伝家の宝刀を抜く (to play one's trump card).

• 交こう渉しょうが難なん航こうしたが、最さい後ごに伝でん家かの宝ほう刀とうを抜ぬいて値ね下さげを認みとめさせた。

  The negotiations were tough, but in the end I played my trump card and got them to agree to a price reduction.

expression, noun

treasured family sword

Original literal meaning: a prized sword passed down through a family. Now mostly encountered in historical or explanatory contexts.

• この刀かたなは当とう家けに伝つたわる伝でん家かの宝ほう刀とうで、先せん祖ぞ代だい々だい守まもってきたものだ。

  This sword is a treasured family heirloom passed down in our house, protected for generations.