What's the name of the bamboo mat for writing brush?

Honey, you're talking about the pen curtain. A tool that can be used to wrap a brush and then carry it conveniently.

I guess you are a calligraphy lover. In fact, tools are also very important when writing calligraphy. First of all, if it is paper or paper, it is ok for beginners to use tassel paper.

I think the pen should be the most important, if you want to buy a writing brush.

I suggest you find this article and read "Top Ten Brush Brands in China (with Brush Selection and Maintenance Methods)".

This paper introduces the selection and maintenance methods of brushes in detail. I hope it helps you.