Kuretake Sumi Ink 60:
"Sumi ink" is a professional ink which its black color is very intense. Very fluid, it can be used with a pen or a brush (you can even fill a reservoir brush with it as this ink won't clog your brush contrary to other asian inks, but rinsing after use is needed). Its fluidity prevents from any smudge and the rendition is a perfect matte black.