Is the TWSBI Kai Worth It? My Honest Long-Term Review

Grass Padrique | The Fabulous Scientist

I got my TWSBI Kai when it was first released through a pre-order from Everything Calligraphy back in October 2023—right when I was still tumbling headfirst into the fountain pen rabbit hole. At the time, I had this itch to own something “rare” or “limited,” and the Kai just happened to be the most attainable option within my budget with my modest pay as an Instructor at UP Diliman. Fast forward to today, and I find myself revisiting this pen after it sat quietly on my shelf for months—almost like rediscovering an old crush who still looks annoyingly good.

The Kai is a piston-filler, very much in line with the dependable DNA of TWSBI pens. Its acrylic body features a striking mix of indigo blue, French ultramarine, and black. The real star, however, is that ultramarine section—it has this beautiful chatoyancy that catches the light in the most hypnotic way. And yes, I fully admit: I am a sucker for chatoyant (or pearlescent) pens. It also comes with rose gold trim, nib, and clip, which adds a bit of understated elegance without screaming for attention.

Writing with the Kai is exactly what you’d expect from a TWSBI pen – smooth, reliable, and just a little bit addictive. The nib performs similarly to those found in the TWSBI Diamond 580, and in my experience, it holds its own against my trusty TWSBI Eco and TWSBI Swipe. The pen is lightweight yet well-balanced, with a girth that makes long writing sessions comfortable. It uncaps in about two turns, and one small but notable detail: the cap features an engraved logo—something you don’t usually see in TWSBI’s more common models, which tend to stick with the red emblem. I can’t imagine red emblem on Kai so the engraved logo added uniqueness to this pen to all the other TWSBI pens available now in the market.

Another thing I genuinely appreciate about all my TWSBI pens is their reliability—even after long periods of neglect. I’ve left them inked and untouched for months, yet when I pick them up again, they still write without fuss. That kind of consistency is something I’ve come to value more over time, especially as my collection grows.

I’ve also used a variety of inks in them, including shading and shimmer inks, without running into any major issues. In one instance, I had my TWSBI Kai inked with a heavily shading ink from Vinta Inks. After sitting unused for quite a while, it did need a little encouragement. A single drop of water on the feed was enough to get the ink flowing again, and it went back to writing smoothly without skips.

Now, the reason this pen spent so much time in storage isn’t due to any flaw—it’s actually the opposite. After nearly losing my Kasama Una (my most expensive pen to date), I became overly cautious about carrying anything that looked even remotely premium. And the Kai definitely looks premium. Let’s be honest: losing a beloved pen is a special kind of heartbreak. So, into the shelf it stayed for months, only occasionally writing with it when I miss it (imagine Gollum bringing the ring out just to look at it before shoving it into his pocketsess).

That said, the Kai isn’t without quirks. It has an ink window, which is a great feature in theory, but because the rest of the body is opaque, I often misjudge how much ink is left. More than once, it has betrayed me mid-writing session with a dramatic “I’m empty” moment. Still, that’s a minor inconvenience compared to everything it gets right.

Today, the Kai remains one of my favorite pens, one I reserve for pen meetups where it reliably sparks curiosity, mostly because not many people in my local fountain pen community own one. Compared to the Eco and Swipe, this pen feels noticeably sturdier, thanks to its thicker acrylic body. I’ve had my Swipe’s cap crack within months (tragic, because the nib was fantastic), and I still baby my Eco because of similar cracking concerns I’ve heard from others. With the Kai, though, I feel a bit more at ease. It is solid, dependable, and built like it actually wants to stay in one piece.

All things considered, the TWSBI Kai is a beautiful, well-crafted pen that feels a little more special than TWSBI’s usual lineup. I’m genuinely glad I picked it up during its first release, and I do hope TWSBI produces more models like this. It’s sturdy, eye-catching, more affordable than most premium brands and models, and just unique enough to make you feel like you’ve got something a little different in your collection, and sometimes, that’s exactly what makes a pen worth holding onto (very tightly, preferably).