Aduki bean soup can be sweet, or it can be not. Aduki bean soup can be had on its own, or it can be had with other stuff. Aduki beans are high in protein and low in fat. Oriental girls are taught by their mums that aduki beans are good for their health, especially when they are on their periods.
To prepare, soak beans overnight, first boil in water then simmer (add extra water if it gets dry) till the beans turn soft and the water turns soupy and pasty. Add sugar if preferred. Add tapioca or oatmeal if preferred. Add nothing if preferred.
You may find the name of aduki bean alien to you, but if you ever munched a mochi with a brown-ish, purple-ish filling that is sweet and can put a big smile on your face, you have definitely had aduki beans already.