There's so many different types of soy sauce. The aged
ones have even more umami, more deepness of flavor. There's
white soy sauce, if you've never seen it it's actually
clear in color. It tastes like soy sauce but it's
white and that's used on dishes you don't want to
see the darkness. Like wine, the darker it goes the
deeper in flavor but funny enough, the dark, dark soy
sauce isn't as salty, it's just deeper in flavor.