Pilot Iroshizuku Fountain Pen Ink - Take-SumiPilot Iroshizuku Fountain Pen Ink Take sumi (bamboo charcoal): Take sumi has been used in Japanese homes since ancient times as a water purifier, to control humidity levels and for its healing properties. The black emulates the deep, rich black of take sumi, so familiar to the Japanese. Pilot Iroshizuku Take Sumi, aka Bamboo Charcoal, is made in Japan and boasts a dark black color, some medium black sheen, and medium water resistance. Fountain Pen Ink