Since it takes too much effort to boil the adzuki beans from scratch, I used canned adzuki. This made the seasoning a lot simpler as well.
Once, when I made 'itoko-ni' (vegetables boiled in miso), from scratch, the adzuki beans came out too hard. That's when it dawned on me to use canned adzuki.
There's no need to add any sugar with these pre-cooked beans. All you need is the soy sauce.
Enjoy Japanese food around the world.