I participated in the Susemai ink testing program, and it was a very good experience. I was grateful to be allowed to test Black Balled, Black Cat, Blue Cashmere, Red Cashmere, and Too Blue Cashmere. Unfortunately, I signed up to participate late, and those are all the ink colors that were left, so I was unable to compare the entire line of Susemai inks, but I enjoyed the ones that I did get (with the exception of Too Blue Cashmere.)
My main goal in testing new inks is to find some ink that would make good pen and ink drawings with water washes. So typically, when I draw in my sketchbook, I will make a pen and ink sketch, followed by a wash with a waterbrush to make shadings in the sketch. I personally like the look of drawings where the original pen lines are crisp and permanent, but some color washes off to shade. I do not like inks that are so water soluble that the original pen lines are washed away. That is my personal style, so what I prefer in an ink for drawing may be different than what other people prefer. That said, I evaluated the Susemai inks that I obtained for their characteristics in an ink wash drawing. I drew an apple for each to keep it consistent.
I concluded that the Susemai inks although intense and nicely colored, are too water soluble for my preference during a water wash. All of the ink lines are very easily washed away. If you are not interested in ink wash sketches, this would at least help you determine the waterproof-ability of these inks. None are particularly waterproof. Hope this review helps people.