SANJIESAN LORE / Marks and production
Check the mirror relationship on a fictional seal
A mark pressed by a tool has a relationship to the tool face. The U.S. Mint explains that coin dies carry a reverse design which transfers to a positive impression. For an original fantasy prop, that basic reversal is a useful drawing check; it does not make the invented object a real coin or an authenticated historical seal.
Choose a harmless original mark
Invent a simple workshop mark with an asymmetrical element, such as a short bar beside a curved line. Avoid using a real government or brand emblem. Draw the intended visible impression first, then make a separate view of the pressing face. If you include writing, keep an ordinary readable reference beside both drawings. The asymmetry makes an accidental reversal easier to spot than a perfectly symmetrical symbol would.
Keep tool and impression views labelled
Place the two studies next to a sketch of the object receiving the mark. Label the tool-face view and the finished impression in the working reference. A texture artist seeing only a cropped image should not have to guess which one to use. If the story requires a faulty impression, specify the visible fault separately; a misplaced feature and a reversed entire design are different clues with different implications.
Use the clue at a believable viewing distance
Write a scene where someone notices the asymmetrical feature. Decide how close they are, what light is available and whether they have seen the correct mark before. Do not expect a character across a hall to inspect a tiny impression just because the illustration gives readers a close-up. The useful result is a prop whose making and observation agree, rather than a microscopic clue that becomes visible whenever the plot needs it.