Review on Kuretake Fude Brush Pen - Fudegokochi (LS1-10): A Versatile Japanese Calligraphy Tool with Exceptional Precision and Control by Morgan Gilmore

So far so good. I've been trying out a few new brushes lately. This is one of my favorites. Standard thickness and length, there is a tank window for ink observation. I haven't used them long enough to run out of ink so I can't comment on how long the pens will last. nor what is good. It's fairly easy to get thin, even brush lines when needed, while still allowing for variation when needed. For a wider range of line qualities and larger areas of black fill, you'll need a different, thicker brush. Even for very thin areas, you'll probably need a brushless eyeliner like a Copic or a Micron.