Lives up to its name; flexible and smudge-proof indeed! Also great for beginners with its short tip which is easier to control than long-tipped brush pens.
Recently bought my 5th kuretake mangaka pen.. loving it!
I use this for inking my drawings, and I am happy with the result! The flexibility of the pen gives the drawing a smooth "thin" and "thick" strokes, which gives the drawing interest. I already have the sepia tones and I am thoroughly enjoying both the fine and medium tip! It's also good for inking larger areas, esp black or brown hair and shadows.
If you're trying out brush calligraphy for the first time, this is a great tool to practice on. Easy to control, and ink flow is consistent. It glides on paper smoothly. And its price is a huge plus! I love this and I think I'll do more drills now because of this.
I got the black, fine tip and it was surprisingly easy to use. It's one of the fude pens I've had that is very easy to control especially when you use it for modern calligraphy. I wish this had more colors available because it's relatively affordable :)
Although it has flexible on its name I'd say the pentel touch is more flexible haha but overall, it's a nice pen. (got medium tip)
Good for calligraphy especially if you have heavy hands. The ink is also solid and the tip doesn't break easily.