Heat 1 tbsp sesame oil in a small or medium-sized pot.
While the oil is heating, dice your celery and onions.
Once the oil is hot, add your celery and onions to the pot. Cook until onions are translucent, stirring as needed. (Onions will be soft and no longer white - you should be able to almost see through them.)
Once your onions are cooked, add your stock, ginger chunks, and most of your green onions, saving some for garnish.
Simmer this for about 15 minutes. The longer you simmer, the stronger your ginger flavor will be.
While your broth is simmering, create your arrowroot slurry by mixing your water and arrowroot in a small bowl. (Do not add dry arrowroot to your soup - it will clump up and look like snot chunks.)
While your broth is simmering, also whisk together 5 - 6 large eggs, using 6 if the eggs are on the smaller side.
Next, fish out your ginger chunks with a slotted spoon.
Mix in your slurry and bring the broth back to a rolling boil. At this point you will add your black pepper, white pepper, Umami powder, and salt.
Cook for about 5 more minutes and then give the pot a stir so that the broth is spinning (like toilet water ;) and slowly pour in your eggs. Continue stirring as you pour in your eggs to prevent big egg chunks from forming.
Cook for another 2 - 3 minutes to fully cook the egg and then spoon into bowls.
Garnish with thinly sliced green onions and salt and pepper to taste. I beg of you, LET THE SOUP COOL BEFORE EATING. Seriously. It looks and smells amazing, but it will be SO HOT.