I saw a question of what kind of hair a particular brush had. It was about Takeda. 

Some companies make it clear  by naming their brushes after brushes’ hair.

Chikuhodo Z series are made with grey squirrel. T series are with goat saikoho.  Hakuhodo says G series are mainly made with grey squirrel and goat though they call them ‘blue’ squirrel.’

Hakuhodo naming is simple. It is easy except that many G series have no number on handles.  I  sometimes spend time on figuring out brushes’ numbers before sending them out. A shop says people touch and try at counter so they don’t care about numbers. Not good for me…

Takeda naming always puzzles me. So I asked a shop how they name it. They didn’t know… but promised to get back to me. 

They inserted a memo into a package sent to me::

For example,
16RSEPSQU(W) in the picture above.

16  is the length of a ferrule 16cm.
RS is a round style.
EP is European dressed Pine squirrel. (European dressed makes hair more straight while Nippon (Japan )dressed is not :NP)

SQU is a squirrel and W is white top.

Others  are:
WF is Tsubaki 椿 seires 
OV is oval
SOV is super oval. 
D is dense
EXS is extra saikoho 

If these make sense to you, great. I did not pay much attention so I preferred simple naming like Chikuhodo and Hakuhodo. 

On the contrary, Koyomo makes its product lines small. I guess they sell very few but expensive products in a similar strategy  to MAC (computer ) . Chikuhodo may be the same, but they make many limited brushes. 

I know many of you are more knowledgeable than I, 
but please let me know if you have a question if any, whether it is related to brushes or makeup. 
It will be good for me to know more!