Sword Stained with Royal Blood (Chinese: 碧血劍) is a 1981 Hong Kong film produced by the Shaw Brothers Studio, directed by Chang Cheh and starring the Venom Mob.

After his father, a Han loyalist and hero, is betrayed by the Emperor and sentenced to death, Yuan Chengzhi is spirited away to the reclusive master of the Lung Yau school of martial arts.

Things get a lot more complicated when a trio of angry martial artists storm the household and accuse Wen of theft.

As a result of his intervention, Yuan's skills draw the attention of the master of the house, who recognizes the kung fu techniques of his arch-enemy.

As hidden truths about the Wen clan and their dark part are revealed through flashbacks, Yuan finds himself forced to fight their infamous Five Element Array in order to complete his quest and escape in one piece.