Factual error: When the God Skills Society disciples build the altar in front of Ching's family temple, they just cover the horizontal ladder-like part with only a cloth strip and then place two candles and a heavy bowl with incense sticks on top without making the cloth sag between the rungs or the items fall off, since there is no solid board underneath.
Ninja In The Dragon's Den (1982)
1 factual error
Directed by: Corey Yuen
Starring: Hiroyuki Sanada, Jeong-lee Hwang, Conan Lee, Po Tai
Continuity mistake: When Jen Moo ambushes Fukoda in his house, he kicks part of the waterwheel's gear against him, jamming it solid and pushing him through the wheel into the river. But in subsequent scenes, the wheel turns again, and it is completely undamaged.
Trivia: The 'torpedo-digging' trick Jen Moo uses in the final fight is a standard trick of all Hong Kong ninja movies made in the 80's.