In novels, the difference between an open line and a hidden line usually referred to the clues of the story. Bright lines refer to direct and clear instructions or hints that can be directly perceived by the reader, such as conversations between characters, plot turning points, events, etc. Hidden lines were used to convey information through indirect means such as hints, metaphor, and details. It was not easy for the reader to directly perceive the information, but it could be inferred and guessed through other means, such as the psychological changes of the characters, background stories, plot arrangements, etc. Both the overt and underhand methods had their own advantages and disadvantages. The method used depended on the plot and theme of the novel. Bright lines could make the story clearer and more compact, but it could also lead to the reader's understanding of the plot being too simple. Dark lines could make the story more complicated and profound, but it could also lead to the plot being too obscure and difficult to fully understand. In novel writing, one could create a story full of imagination, tension, and depth by cleverly using the overt and hidden lines.