Kuretake Zig Letter Pen CocoIro Pen Refill - Super Fine - Black

Of all the ink colors in this line, black is the smoothest I've used!
It does take some getting used to, but the tricks this pen can do are cool! Writes variable line widths, no skipping, smooth flowy ink, even when you write fast. Its not scratchy to me, and I am very picky about scratchiness (Hi-Tec C 0.25 mm, I'm looking at you!).
Writiing in English or Japanese (I can't write in any other languages but I'm sure it handles just the same) looks very pretty and you can even get a lttle fancy with your script uusing the Letter Pens, without even trying too hard.

Yes, you can use these refills alone without the pen body, but I suggest you get at least one pen body to try oout. I pprefer using the pen body not just the refill alone.
(aand, sorry for the typos, I'mtyping on my phone!)

The tip took a few paragraphs for me to get used to but now I love it. I think this will be my new favorite pen. The ink is smooth and doesn't bleed through. I bought this along with the pink body. I really like them both!

It took a while to get it writing at first, but now it's very nice! not too runny when I'm writing.

This is hands-down the smallest tip I've ever had the pleasure to use. It writes so finely, that I was able to write a poem of 107 words on a 2" post it note, with margins around the outside and between the paragraphs! I was amazed at the quality of the writing, with very smooth, dark ink. The pen "refill" itself handles just fine, but I used it with the Kuretake Zig Letter Pen CocoIro Pen Body - Light Blue, and it was really very pleasant. Definitely recommend for fine/small writing!