1. Soak kelp in cold water overnight, wash and cut into diamond-shaped pieces. Soak the soybeans overnight to make them stew faster. You can also soak them without soaking them.

2. Wash the pig's trotters and chop them into pieces, add cold water to boil, reduce the heat to low and beat off the foam. Add ginger slices,

3. Add soybeans to 2, simmer over low heat, then add kelp, simmer for half an hour, add green onion, salt, a little MSG, and remove from the pot.