Chu Shu is part of the autumn season limited edition of Sailor Jentle inks. It is a grey ink that has a purple tone to it. It reminds me of a muted Diamine Damson. It is not a true grey ink. Overall, this is an interesting colour. It is dark enough for some corporate use yet has some subtle colour which makes it interesting plus it has some shading.
Sailor inks comes in a simple low, round bottle. Nothing as onate as the Iroshizuku or Edelstein inks. The design of the bottle might make it hard to get the last drops from the bottle. However, Sailor has a plastic reservoir. Just turn the bottle upside down (capped, of course) and let the reservoir fill up and then fill the fountain pen from there!