Combine the natto, sauce and mustard that come with the natto pack. Mix.
Add the rest of the ingredients to the natto from Step 2, and mix together. I normally use this much of onion and kimchi. Adjust to taste.
It's done!! As you mix in the vinegar, you can pour this over a salad like a salad dressing.
Story Behind this Recipe
I added vinegar to the recipe I saw on a TV program. Adding vinegar made it much easier to eat. I don't tire of the taste even if I eat it everyday.
The volume of lactobacillus increases by feeding on bacillus subtilis natto. Onions contain oligosaccharide that bifidobacterium feeds on. And olive oil aids digestion. If you are not constipated, you can omit the olive oil. But you must add the vinegar! If you let it rest overnight, it ferments even more and will be even more effective.