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.

Hey, so the Kuretake Fude Brush Pen Extra Fine, which is also called the Fudegokochi (LS4-10S), seems like a solid pick if you're into detailed drawing or writing.

It's got this extra-fine tip that's a bit stiffer than a regular brush pen, which means you can have more control and precise lines — pretty handy if tons of detail are your thing.

But here's the catch: it's not waterproof. The manufacturer actually mentions that the ink is aqueous dye, so it'll bleed if it gets wet. That means if you're planning on using watercolors or mixing in other wet mediums, you might run into some issues.

From what we found, folks seem to like how this pen creates clean lines, making it awesome for detailed work or fancy handwriting.

The stiff nib helps with controlling line thickness too. Though, just a heads up, some have noticed that ink can gather at the tip, and a few felt it ran out faster than expected. Luckily, you can get refills for it.

Also, a few people have said there's some bleeding, especially on certain papers or when the pen mixes with wet supplies.

The manufacturer not being waterproof seems to fit with what they've experienced. There have also been occasional mentions of ink flow inconsistencies, and some got pens that seemed low on ink from the start.

In short, it’s a great pen if precision is what you’re after, but definitely think about whether these quirks might cause any issues for what you're planning to use it for.

The Kuretake Fude Brush Pen Extra Fine (LS4-10S) gives you a bit of flexibility when it comes to line width, depending on how much pressure you use and your technique. The manufacturer describes it as 'Extra Fine,' so you can expect thin, precise strokes. But exact measurements? Not really available. It's the nature of brush pens, where line thickness can vary a bit.

The pen itself is flexible enough to go from very fine lines to slightly thicker ones if you apply more pressure. Our research suggests that folks like artists and calligraphers dig it for detailed work and precision line illustrations.

It's worth noting the pen isn’t waterproof. It works best for dry applications, offering clean and consistent lines that's great for sketching and writing.

Just keep in mind that the water-based ink can bleed if it gets wet, which makes it a poor fit for water-based art projects. If you’re working with watercolors or need something for a wetter environment, you might need a different pen—one that's specifically waterproof.

In essence, the Kuretake Fude Brush Pen Extra Fine is fantastic for dry, precise work. Whether you're into illustrating, sketching, or calligraphy, this pen handles dry media beautifully.