I came across it in my student years in Japan and I call it by its Japanese name. However, this mighty sensual assault on your taste buds was invented in China's Southwest, Szechuan, as dou-ban-jiang (豆瓣酱).
There are two types of it: plain and spicy. I am no big fan of the plain version (it is just smelly and salty), but the spicy one la-dou-ban-jiang (辣豆瓣酱) is one of my favourite condiments. It is indispensable in mapo dofu (麻婆豆腐), the Szechuan numbingly hot toufu, mince and aubergine stew, as well as dandan noodles (擔擔麵). I also like to top steamed rice with it when I am going through a cook's block. It works superbly plain as dressing for avocado.
Korean gochujang looks and tastes somewhat similar to it but had a different flavour because in Korea they use ground sticky rice instead of beans and the fermenting process is different.