The natural fermentation brewing process of "Zhongba Mushroom Soy Sauce" is derived from the traditional formula of the imperial soy sauce during the Daoguang period of the Qing Dynasty. It selects non-GMO defatted soybeans from Northeast China and wild mushrooms from the northern part of Zhangjiakou as the main raw materials. It is naturally fermented after 180 days of sun exposure and night dew, and refined through multiple traditional fermentation and brewing processes. Zhongba Mushroom Soy Sauce has a series of products such as handmade special (special grade), double mushroom (special grade), crafted (special grade) and special brewed (first grade), dark soy sauce and light soy sauce (third grade). Information source: Mianyang Intangible Cultural Heritage Protection Center Information source: Mianyang Intangible Cultural Heritage Protection Center