When you're choosing between the Kuretake Fude Brush Pen Extra Fine (LS4-10S) and Tombow Fudenosuke pens, there are a few things to consider.

Starting with the Kuretake Fude Brush Pen, it's worth noting—based on the manufacturer's description—that it uses aqueous dye ink, so it's not waterproof. If you're mixing it with watercolors or other water-based media, be careful—it could smudge or bleed, and our research suggests the ink might not stick around as long as you'd like.

Some folks have noticed issues with the ink running out pretty quickly too, which is something to think about for bigger projects.

On the other hand, the Tombow Fudenosuke pens are popular among artists and calligraphy fans because they offer both hard and soft tip options for different styles. Like the Kuretake, these aren't waterproof either, so water exposure might require some caution.

People tend to like the Tombow for its durability and ability to draw fine lines, which is great if you're into detailed work or picking up calligraphy. It's really a matter of what feels right in your hand, as both brands offer quality tools with slightly different feels.

So, if you're focusing on dry work and need extra-fine lines, both Kuretake and Tombow have got you covered. But if your art involves wet media, you might want to look for pens that can handle water a bit better.