I'd heard this one was Iroshizuku's periwinkle blue. It looks close. I like a good periwinkle color. It's just fun to say. This seems a little drier than some of the Iroshizuku inks I've tried. Just a bit. Still flows good and doesn't feather, bleed, or insult your mom. As standard for Iroshizuku. Did better with the water test than I was expecting. It's close in color to Namiki Blue. (which I realize now I forgot to add to the comparisons on the sheet)