The Darkest Sword, also known as Hei jian gui jing tian (), is a 1970 Hong Kong action martial arts film directed by Lung Chien, produced by Yuan Hsiang Wu, and starring Ching-Ching Chang and Pin Chiang.
Tun-Shan is grieved because he unintentionally killed an enemy and doesn't want to fight anymore. Then, he destroys his sword. Meanwhile, Su-Chen, in love with him, convinces him to start fighting again.