Description Sailor Shikiori Chu-Shu fountain pen ink is is now available in cartridge form! The packaging is practical and adorable, and the name of the ink color is embossed on each cartridge! Sailor fountain pen ink is smooth-flowing and specifically formulated to be safe for all fountain pens. Chu-Shu is a deep, dark shade of purple that in certain light can look blue-black or even black.Sailor fountain pen ink cartridges are proprietary, and only fit Sailor fountain pens that accept cartridges.Having trouble deciding between colors? Use our Ink Comparison Tool to quickly and easily view different colors side by side.We offer Free Shipping on all orders over $50 for US customers, and for orders over $250 for our Canadian customers.