Pilot Iroshizuku Tsuyu Kusa Ink Bottle

Pilot Iroshizuku Tsuyu Kusa Ink

Pilot Iroshizuku Tsuyu Kusa Ink is part of the Pilot Pen Company’s luxury ink line, known and loved throughout the pen community. Pilot was one of the first ink companies to raise the bar with their inks, both in ink properties but especially the presentation with their Iroshizuku brand. Pilot Iroshizuku inks are considered luxury inks with its price point at the peak of what the market would bear. Pen lovers soon got over the initial sticker shock and Pilot Iroshizuku inks have been an international hit. Recently, however, Pilot Pen Company has lowered their retail price of the Iroshizuku ink brand and with the additional discount we offer, Pilot Iroshizuku ink are now in the mid range ink world.

Also known in English as Asiatic Dayflower, Pilot Iroshizuku Tsuyu Kusa ink is a beautiful blue color and one of about 5 blue colors in the Pilot Iroshizuku line. The deep royal blue is darker than the lighter turquoise color of another favorite, Iroshizuku Kon Peki ink. It’s a fantastic everyday royal blue color that has both some shading and sheening traits. The name Iroshizuku was created using two Japanese words meaning droplets of color, which are found in Japan’s diverse natural world.

Continuing reading for a chance to win the bottle of Pilot Iroshizuku Tsuyu Kusa Ink we used for this review.

Pilot Iroshizuku Tsuyu Kusa Ink Review

Pilot Iroshizuku Tsuyu Kusa Ink Review

We found the following traits during our review of Pilot Iroshizuku Tsuyu Kusa ink that you may find helpful when choosing your next ink color:

Testing Factors

We used a French made J. Herbin spiral glass dip pen on Rhodia dot pad paper for our review of Pilot Iroshizuku Tsuyu Kusa ink. The glass dip pen has a tip that is similar to a fine fountain pen nib.

Bottle Sizes

Pilot Iroshizuku Tsuyu Kusa ink comes in Pilot’s recognizable Iroshizuku ink-well glass bottle, one of the best ink display bottles on the market today. The 50 ml. bottle is heavy weighted and has a distinct internal ink well that allows for using every last drop of ink. The lid is large faceted, making it easy to open as well as to fill your pen.


Pilot Iroshizuku ink started a revolution of “luxury” inks and its display, bottle, and price. However, within the last year, Pilot has lowered its retail price of its Iroshizuku ink to $25.00, which makes it much more reasonable. With our discounted price, Pilot Iroshizuku Tsuyu Kusa ink is now firmly in the mid-range price category, although the quality, display and bottle have not changed one bit.

Dry Time

We found a dry time of approximately 11 seconds while testing Pilot Iroshizuku Tsuyu Kusa ink, which is a little longer than other Iroshizuku ink colors. Pilot Iroshizuku Tsuyu Kusa ink has good saturation and wetness that account for the longer dry time.

Bleed Through

We did not see any bleeding during our review of Pilot Iroshizuku Tsuyu Kusa ink on Rhodia dot pad paper. Even during the cotton swab test, we did not experience any bleeding. Different papers may produce different results.


During normal use we experience no feathering using the glass dip pen on Rhodia dot pad paper. During our water test we did see some line distortion and slight feathering. This is to be expected as Pilot Iroshizuku Tsuyu Kusa ink is not a waterproof ink.

Water Test

We ran a wet cotton swab over the dried ink sample and saw some slight feathering, line distortion and color smearing. All of these results are expected with a non-waterproof ink.


Like many other Iroshizuku inks, Pilot Iroshizuku Tsuyu Kusa ink produces nice shading. We are able to achieve a predominate dark blue and a lighter shade of blue coming with a drier stroke of the pen. Pilot Iroshizuku Tsuyu Kusa ink will also produce a red sheen with the wettest strokes on certain paper.

Conclusions about Pilot Iroshizuku Tsuyu Kusa Ink

Pilot Iroshizuku Tsuyu Kusa ink is a nice shade of blue, has great flow, is safe for even your most expensive fountain pens and is now reasonably priced. The presentation and ink well type bottle are exceptional and one of the best in the business. There are only 24 Iroshizuku colors produced, making this ink line one that you slowly collect all of its colors! If you are a blue ink lover, Pilot Iroshizuku Tsuyu Kusa ink will not disappoint. Happy Writing from Japan!

Enter to Win

Enter to win the actual bottle of Pilot Iroshizuku Tsuyu Kusa ink that we used in this ink review:

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This ink reminds me of a kind of tea that I had that’s made with blue flowers. I wonder if it’s the same flower!

Jacob Thebault-Spieker

I’d love to see a comparison between Iroshizuku Kiri-Same and Fuyu-Syogun


Pilot Iroshizisuku inks are some of my favorites. I have to find a pen that they don’t work well with!

Patrick Tinney

I love the Iroshizuku inks I have tried. Chiku-Rin is a very interesting green.

Jessica Ozburn

Awesome giveaway! Thanks for the chance-blue inks are my favorite!

Ron Parish

I still think you should pick an ink producer, then talk about an ink in each color spectrum.


Another awesome giveaway!

Mark Junk

Always looking for a new bl9 and this is one I haven’t tried yet.

Scott DiGello

My favorite Pilot ink is Pilot Iroshizuku Kon-Peki.

Teresa Fuhrmeister

This is a beautiful color. A few days ago I was exploring the names of the Iroshizuku Inks.
It turns out that the person that lived here before I did, planted some of these Asiatic Dayflowers in the landscaping. I did not know what the mysterious little flower in my yard was until I researched this ink. I am impressed with how bright they are for such a small flower.


That blue looks pretty vibrant. Nice!


Oooh! One of the Iro blues that I haven’t tried yet. But I definitely like this shade.


Have you guys done Colorverse strelka?


I’d love to see water tests where the writing sample is completely immersed in water for a short time — at least a minute, but 30 minutes would be ideal — to give a better idea of the ink’s practical water resistance.

Amy R

What a beautiful blue color!

Cyriacus Okolie

I am really curious about the Iroshizuku Kon-peki.

John B

Can you ever truly have too much ink? I’ve honestly never met an ink I didn’t like.

Geoffrey Dunn

Beautiful blue! Thanks for the chance to win a bottle!


A great shade of blue

John Stein

This might be my favorite ink if I win (wink, wink)! Robert Oster Fire and Ice is my current favorite.


Iroshizuku Tsuyu Kusa is a nice blue… An in-betweener maybe. Grays seem to be picking up in popularity though. I love my fuyu-syogun. Would love to see more of those!

Mark Nelson

Great ink

James McCarty

Tsuyu-kusa has been a favorite of mine for a long time. You might consider reviewing Platinum Mixable Aurora Blue.


Very helpful when reviewing the water resistant part. Thank you!

Andrew Mulnix

This one looks pretty good


anybody can translate Iroshizuku Tsuyu Kusa ?

John Stein

I believe it is “dayflower”.



Ethan Ball

This ink looks really nice, it’s lighter without being washed out. Ever review Baystate blue?

Toni C

What inks would you recommend for use with a Lamy Safari XF nib?

Melanie Wittman

Really beautiful…love this shade of blue!

Desmond O'Neill

I do like the Iroshizuku inks, but I still love Waterman Serenity Blue!


WOW !!


Please review Monteverde’s Permanent Blue next, and also do bleach and acetone tests on it to see how permanent it is.

Esra Karakas

Gorgeous color

Ged Alangui

I love blue inks and I’ve only tried kon peki among Iroshizuku inks. Awesome giveaway.

Michael Simon

I would like to see reviews of Krishna inks as I haven’t tried any yet.

Tejashree Kulkarni

What a great blue colour! And loved the thorough review. Thanks for a chance to win it.

Unjuan Equis

Iroshizuku is so heavy on blues that sometimes I can’t get them straight. My favorite is Kon-peki

Michael johnson

Beautiful blue!

Michael Kwan

The Pilot Iroshizuku inks have become my primary inks now. This one would fit right between the Kon-Peki I have at work and the Tsuki-yo I have at home.

Ana G Csiky

Such a beautiful blue!

Ana G Csiky

Thank you for the giveaway! This is such a lovely shade of blue!

Unjuan Equis

There are so many blues in the Iroshizuku line that sometimes it’s hard for me to tell them apart. My favorite is still Kon-Peki.

Mike Solinas

Beautiful blue! Iroshizuku Syo-Ro is a favorite.

Ali Karakas

Wow amazing color

matthew fitzgerald

I really like the bottles


Love this blue 😀

Cheri Millard

This is a very nice looking blue.

Cheri Millard

I like the look of this ink