Rinse green split peas and soak in enough water overnight.
In a large deep pan, put the peas, a bay leaf, and about 1L water.
Cook them for 20 minutes on medium-high heat. Get rid of the foam on the surface as it comes out. [Tip] Add a splash of water if necessary to avoid getting burnt. Meanwhile, cut all the veggies into small pieces.
Add the veggies, soy sauce, and shio-koji (or white miso) imto the pan. Cook for another 20-30 minutes until tender. Give it a stir occasionally.
[Tip] The texture should be thick instead of watery. To make sure, try stabbing a spoon onto the soup surface. Does the spoon stand nice and upright without falling off?
Add black pepper, salt, and optional shichimi. Cool it down for a moment to get rid of the heat.
Blend everything with a blender or a hand blender. You can leave it a bit rough if you prefer tiny chunks of the ingredients.
Serve with fresh bread, and enjoy!