The Kuretake brush in question tapers to a very small tip and it is fantastic for the thinnest of lines. The general shape of the bristled tip comes into play here and I will do my best to explain why with a story. I once knew a sign painter, a 60 year old guy whose clothes were perpetually covered in paint and whose hands were more cracked than the pepper at a fancy restaurant. He also did pinstripes for auto body places. I was curious, so he brought in his pin striping kit. To my surprise the brush was almost no handle but the bristles were four inches long. I asked about it and he showed me, once the very tip of the bristles touched the surface of whatever he was painting on, the sheer amount of distance in bristles between his hand and the contact made any hand shake or tremor disappear. So the length of the brush acts like an insulator or a shock, absorbing the inconsistency.
This brush with the longer than average tip has the same effect, very smooth lines, especially when drawing towards you with a low degree angle. This will also produce a consistent line width, For more variance and thinner lines try it out at more of a 90 degree angle, but watch your hand control. I found myself tilting it to a low angle for the smooth, consistent lines when outlining and longer ink strokes, and switching to a high 90 degree angle for details and finishing touches. The wide variety of uses makes this a versatile enough brush to be the only one I keep in my bag at the moment.