What is the origin of Ghost Festival on July 15?

Ghost Festival originated from the Buddhist "bonsai". Originally, this festival had nothing to do with the Central Plains in China, but it happened that in the local religion and Taoism in China, the official forgiveness day of the Central Plains was also on this day. Therefore, the story of "Orchid Club" is integrated with the Central Plains, adding many China elements, such as combining with Confucian filial piety, forming a traditional folk festival in China: Ghost Festival and Central Plains Festival. Later, the concept of ghost became more and more obvious from animism, forming a unique culture and a huge ghost system, such as hell, judge, black and white impermanence, Meng Po and so on. And reflected in folk customs, festivals and ghost stories.