Soy sauce is a fermented sauce made from soybeans (soya beans), roasted grain, water and salt. The sauce, originating in China, is used widely in East and Southeast Asian cuisines and appears in some Western cuisine dishes.
Doubanjiang (Chinese: 豆瓣酱; pinyin: dòubànjiàng; literally "beans mixed into sauce") is a spicy, salty paste made from fermented broad beans, soybeans, red chili peppers, salt, and spices.
Douchi (Chinese: 豆豉; pinyin: dòuchǐ), also called Chinese fermented black beans, is a flavoring most popular in the cuisine of China, and is used to make black bean sauce.
Douchi is made by fermenting and salting soybeans. The process turns the beans black, soft, and mostly dry. The flavor is sharp, pungent, and spicy in smell, with a taste that is salty and somewhat bitter and sweet.
Tofu, also toufu (the Japanese Romaji spelling), doufu (the Chinese Pinyin spelling often used in Chinese recipes) or bean curd (the literal translation), is a food of Chinese origin, made by coagulating soy milk, and then pressing the resulting curds into blocks. There are many different varieties of tofu, including fresh tofu and tofu that has been processed in some way. Tofu has very little flavor or smell on its own, so it can be used either in savory or sweet dishes, and is often seasoned or marinated to suit the dish.
(5) Soy milk
Soy milk (also called soya milk or soybean milk) and sometimes referred to as soy drink/beverage is a beverage made from soy beans originating from China.
Other Soy products introduction website
my personal experience :
My french pen pal likes to eat stinky Tofu ; soy milk ; tofu skin (豆腐皮 ) ; oily tofu ( 油豆腐 ) ; tofu pudding ( 豆花 ) . But he doesn't like tofu and soy sauce.