I went to a Yakiniku restaurant (Jambo Hanare) a few months back and the meat slices you could grill yourself were all coated with this delightful marinade for a few minutes.
My best guess is that it contains soy sauce and black pepper but past that I am unsure.
Does someone know more about the ingredients by any chance or has any guesses? Maybe it is even a common thing/marinade in Yakiniku?
by Sefanua98