At the stores sell black inks for oulining ,shading, filling... why is this for ?Not sure what you are trying to ask here?
Why more time??? what black ink must use to fiil in nice and fast ???? Kuro sumi for fill in doesnt exist ???what problem may have if i fill in with kuro sumi outlining ink ????Yes it can, but it may take you more time to do it, and in some cases it may need to be retouched later.
That ink besides being great for the lining, is also pretty neat for you to make your own washes.
Personally i will be trying Xtreme tribal black soon, since i heard very nice reviews from their inks.