Clean the sorted black soybeans by placing them on a damp cotton tea towel spread out on a cutting board. Fold the towel over the beans and rub and roll them gently through the towel. This removes dirt without taking off the skins.

Dry roast beans in a heated cast iron or stainless steel skillet until a nutty aroma is released, they turn golden in color and the skins start to split. Use a high flame until water evaporates, then lower the flame until roasted. Stir gently and constantly to prevent burning.

Place black soybeans with washed brown rice in a pressure-cooker and mix well. Add water by pouring gently down the sides of the pot.

Place the pressure-cooker on a low flame until bubbles begin to arise.

Add a stamp-sized piece of dry kombu per cup of uncooked grain plus beans.

Put on the lid, turn up the flame, and bring to high pressure on a medium-high flame. Place the pressure-cooker on a flame deflector, reduce and cook on a medium-low flame, just enough to maintain the pressure with a calm, gentle hissing sound.

 Cook for approximately 45 to 50 minutes. Turn off the flame and let the pressure reduce naturally (approximately 10 minutes).

After the pressure is completely reduced, remove the cover and gently transfer to a wooden bowl. The kombu may be mixed in with the dish and eaten.