Guan Yu's blade, also known as the Green Dragon Crescent Blade or Guan Dao, is a legendary weapon associated with the Chinese general Guan Yu from the Three Kingdoms period. As a legendary weapon, its precise weight is not well-documented, and various depictions and adaptations may differ in terms of size and weight.

That being said, historical replicas or recreations of the Guan Dao can provide some general estimates. Typically, a Guan Dao replica can weigh anywhere between 15 to 25 pounds (7 to 11 kilograms) or even more. These replicas are often made for martial arts training or decorative purposes, and the weight can vary depending on the materials used, such as steel or other metals.

It's important to note that the weight of a historical weapon can be difficult to determine precisely, as there may be variations and artistic interpretations. The specific weight of Guan Yu's original weapon, if it indeed existed, is not known with certainty.

In summary, the weight of Guan Yu's blade, the Green Dragon Crescent Blade or Guan Dao, can vary depending on depictions and adaptations. Historical replicas or recreations generally weigh between 15 to 25 pounds (7 to 11 kilograms) or more, but the specific weight of the original weapon is not known.