The assassin’s teapot also known as “Liangxin teapot” (meaning two cores in one teapot) is a two chamber teapot which is known to have Chinese origins.
Origin story: It was a wine container used by Chinese nobles for drinking and merrymaking. They used this tool to trick one another during banquets .
It is also rumored to have been an assassin’s tool, by using this tool they could easily mix poison with regular beverages.
Many films use a similar trope when it comes to poisoning. The aspiring murderer ingests a drink poured from the same vessel as that given to their intended victim to indicate the liquid is safe to imbibe. The Assassin’s Teapot is a way one could achieve such a ruse, allowing two different liquids to be poured from a seemingly regular teapot.
The old man on the teapot is one of Eight Immortals of ancient Figures in Chinese Myths, and he represents the God of longevity. People believe that he could bring wellness and wealth.
How the assassin’s teapot works
Taking a peek down the spout reveals what looks like two paths for two chambers:
The trick is simple. Two separate cavities exist within the teapot, exiting via their own paths in the same spout. Each cavity also has an air hole in the top. If the hole for a given cavity is blocked by the pourer’s thumb, the liquid will not flow.
The workings are simple; if air cannot flow into the cavity of the teapot to replace liquid flowing out, air pressure will stop the liquid flowing at all. The concept is demonstrated ably by [Steve]’s 2D recreation, letting us visualize the workings of the teapot quite easily.
There’s also a minor flaw in the design, which should be accounted for, if the spout isn’t designed carefully, sometimes flow from one cavity can dribble into the other. Between this and the chance of getting confused about which hole to cover to pour the poison.
It’s nothing that special. This teapot utilizes what is known as the surface tension of liquids.
In order for the liquid to get out of the pot, air needs to come in, and when the hole corresponding to one of the chambers is closed, air can’t get into the chamber from the hole.
And in this case, the air will try to get into the chamber through the other hole, which is the spout. And at that point, the surface tension occurs between the air and the liquid, preventing it from coming out.
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