According to "The Tale of the Heike," nobles hated Tadamori because he became Tenjobito (a high-ranking courtier allowed into the Imperial Palace). They plotted a surprise attack; however, Tadamori used his wit to save himself by threatening nobles with a silver-plated wooden sword (Tenjo no yamiuchi, or Surprise attack in the Palace)
『平家物語』では武士である忠盛が殿上人となったことを憎んだ公卿たちによる闇討ちが企てられるが、忠盛は銀箔の木刀によって公卿たちを脅す機転によって防ぎ、鳥羽上皇から賞される（殿上闇討）。