I actually got this by asking one of the chefs at a local Hibachi grill. He said he would give it to me only if I could correctly guess the main ingredient. I tasted it and then told him mayo, and he laughed loudly and gave me the recipe.
I use this sauce whenever I make homemade Hibachi style dinner for my fiance and I. :)
Using a fork or a whisk, blend all ingredients together thoroughly until well mixed and the sauce is smooth. Refrigerate overnight** to allow flavors to blend. Bring to room temperature before serving.
***Hellman's mayo is CRUCIAL for the taste of the sauce. Cheap brands do make the taste change significantly! Hellman's is called Best Foods west of the Rocky Mountains, but make sure you get Hellman's!
**The overnight refrigeration is THE MOST IMPORTANT PART!!! If you do not follow this, the sauce will NOT turn out right.