In the eyes of northeasterners, soybean paste is a modified version of northeastern dashi, very suitable for industrial production. The difference in use is not very great.
There are mainly the following differences:
1. odor, although under normal circumstances the Northeast soy sauce has no odor at all. But because there are often a lot of people or restaurant marinade technology is not passable, which leads to the sauce with a little bit of odor, and soybean sauce is not this risk. I recommend Baoquanling soy sauce, which is the most authentic Northeast soy sauce you can buy outside of Northeast China.
2. Soybean paste. Unlike soybean paste, especially Haitian's soybean paste, there are usually no dubs in Northeastern dashi. All the soybean grains are mashed when making the sauce cubes.
3. Salinity. Obviously, Northeast Dashi is much saltier than soybean paste. And it has almost no sweetness. It has a heavier sauce flavor and tends to be a bit stickier as well.