However, I do not eat out much at all. It is overpriced and I am frugal and a good cook. Also, I can't control the type or quality of ingredients used. Thus, I knew I wasn't going to get this detectible sauce very often unless I figured out how to recreate it in my own kitchen. After a bit of research on the internet (where I learned this was a quest for lots of other people as well) I came up with the following recipe. Its not quite the same, but it is close enough for me.
Osaka Ginger Dressing
1/4 cup vegetable oil
2 1/2 Tablespoons ginger root, peeled and grated
1/2 teaspoon sugar
1/4 C sesame seed (toasted or not)
1/3 cup soy sauce
tiny splash of sesame oil (optional)
If you have a Vitamix or other high-powered blender don't bother peeling and grating the fresh ginger. Toss in a hefty knob and let the machine do the work.
I bet you can store it in the fridge for a good while, but I'll be honest and say that when I've made it at home it hasn't lasted long enough for me to find out.
Update April 2018: I now make a variation of this to use as a salad dressing, too.