The “Greed Cup,” also known as the “Cup of Self‑Control” or the “Leaking Cup,” is an ancient Chinese vessel imbued with profound moral and cautionary significance. Typically used for drinking, its core design principle is simple yet powerful: “When filled beyond moderation, the liquid leaks out—reminding us to curb greed and embrace frugality.” While visually resembling a conventional wine cup, the Greed Cup conceals a clever internal mechanism; its body is often adorned with inscriptions such as “Contentment Brings Eternal Joy” or “Refrain from Greed,” along with symbolic motifs like figures holding a “Cup of Self‑Control,” subtly conveying the ancients’ critique of “greed” and their advocacy for “moderation.” In traditional social settings, the Greed Cup served not only as a drinking vessel but also as a tangible medium for imparting ethical lessons—should a drinker attempt to overfill the cup, the liquid would naturally spill out, serving as a gentle yet effective reminder: “Do not be greedy.”​

2. Operating Principle​

The Greed Cup operates on the principle of syphon action—a phenomenon where, by leveraging the difference in liquid levels, a fluid flows from a higher elevation to a lower one once a U‑shaped tube is completely filled. Hidden within the cup’s intricate design lies a sophisticated “mechanism” that ensures this effect.