Le château de Fu Manchu

All of the footage at the beginning featuring a large ocean liner striking an iceberg and sinking is stock footage from the British Titanic movie Atlantique, latitude 41° (1958).

The first scenes where Fu-Manchu is directing the sinking of the liner were the final scenes of a previous Fu-Manchu movie: The brides of Fu Manchu, where he shots his lieutenant who was trying to stop Fu Manchu surpass the maximum of the machine.

Maria Perschy's character is called Dr. Ingrid Koch but on the credits her character's name is given as Marie.

As usual in 'Jesus Franco' movies, the credits of the film contain different (and often incongruous with each other) info in every country's version. While the English version lists Peter Welbeck (nom-de-plum for Harry Alan Towers) as the author of the screenplay, the Spanish version (with a credits sequence that replaces the exterior shots of the castle from the original with a cheesy drawing of a red dragon) lists Manfred Barthel as the author of the story and screenplay, and Jaime Jesús Balcázar as the author of the dialogue. This version also credits some actors (such as Gustavo Re and Osvaldo Genazzani) and crew members not credited in the English version, and the cast order is different as well.

Edited from La vallée de l'or noir (1957)