剣けんを落おとして舟ふねを刻きざむ

expression

not keeping up with the times; being unaware of change; clinging to outdated methods

Idiom from a classical Chinese story: a man drops his sword in a river, marks the boat, and later searches from the mark, ignoring that the boat has moved. Used to criticize rigid thinking that ignores changing circumstances.

• 昔むかしの成せい功こう体たい験けんにこだわるのは、剣けんを落おとして舟ふねを刻きざむようなものだ。

  Clinging to past successes is like dropping one's sword and carving the boat.

• 市し場じょうの変へん化かを無む視しして同おなじ戦せん略りゃくを続つづけるのは、まさに剣けんを落おとして舟ふねを刻きざむ行こう為いだ。

  Continuing the same strategy while ignoring market changes is exactly an act of dropping one's sword and carving the boat.