I've tried many different blues, J. Herbin Saphire and Periwinkle, Pilot's Blue, Parker Blue, and even Platinum Blue Black. This is by far the best ink I have ever used. It flows great, and the color is unbeatable. I need to use blue for office work, and this makes my writing so much more enjoyable. Highly recommended.

I have 9 or more different shade of blue ink in my collection from J herbin to Diamine. So far, in my opinion, Kon Peki is one of the best blue that I ever use. I use this ink with my Tombow Carbon 101 Medium nib. Very smooth and bright but not too bright. It's really hard to explain, very pleasant to the eyes. Although Pilot Iroshizuku is one of the most expensive ink, it worth every penny. Recommended!

Used this ink in a Platinum Plaisir Fountain Pen - Medium 05 Nib - and I'd say they are a match made in heaven.

The blue itself is a very lovely color. I often get some places in my writing that are a lighter blue than others, which can become a very deep blue, and it gives the overall appearance a sort of watercolor feel. While I do say lighter blue, I do not mean anything unreadable, just slightly lighter, enough to give a nice depth to everyday writing.

I've never had an issue with the ink being slow to dry or drippy, seems to dry or soak into my page fairly quickly, little to no bleed (depending on the paper quality).

It's a beautiful every day blue, and while expensive, I highly recommend it. The bottle will last quite a while, so I see the investment being very justified.

I have a few of the Iroshizuku inks, and this is my absolute favorite. The shading on it is very nice. It ranges from a deep blue to a lighter azure, and reminds me of a tropical ocean.

I love this ink. The colour makes me happy.