Pilot's Iroshizuku Kon-peki was the most beautiful blue ink I'd ever tried ... until this. Can't add anything to what the other reviewers said in their comparisons.
The only distinctive thing about this ink is the way it clings to the sides of the plastic sample bottle. Every other ink just runs down the side of the bottle cleanly, leaving nothing behind. With this, there's a distinct residue, not unlike the lacing on a beer glass. Not sure at this point whether that will interfere with getting the last drop.
I bought a sample of Souten to compare it to Sailor Jentle Sky High. Once dry, I cannot tell them apart during normal writing; I can only distinguish them by the amount of red sheen they present where the ink pools in heavy application when doing swabs—Souten has more sheen—and that Souten is slightly bluer than Sky High. Like the latter, it is smooth flowing and worked flawlessly in all my Sailor 1911 L and S pens, with all nib sizes from H-EF to H-B, even in my 1911S 21kt H-M, which is a dry writer. Souten is a hair more saturated and coats the nibs slightly more than Sky High, which is by no means a thin or watery ink to begin with.
If I hadn’t already bought two bottles of Sky High, I would gladly get Souten as a replacement for Kon Peki, which has a tendency to feather terribly on some papers. Other inks that are also similar to Souten in tone are Kobe #17 Shioya Blue, Robert Oster True Blue and Diamine Asa Blue. Of course, all this is based on what my eyes observed or perceived, using my pen and paper combos, and is in no way scientifically measured!
If you are kicking yourself for missing the boat with Sky High, stop it! Souten holds its own.
This ink takes all the things great about Pilot Kon-Peki and just amps it up a notch. The red sheen is amazing and the colour is a very rich sky blue. If you have Jentle Sky High, I would say that you don't need this ink: Sky High is a better price for what you get and also sheens better, if that's what you're after. Only drawback compared to Kon-Peki and other blue inks is that this one takes a little longer to dry.
