It goes to 12!
If you think 10B is the softest grade on the market, note that Taiwanese brand Roxy offers their No. 188 pencil in 12B.
Unfortunately, the Roxy 188 is a scratchy carbon pencil, leaving a line perhaps comparable to – I’m not sure what. Even “hard” compressed charcoal is smoother and more usable.
The “12B” label seems to be a gimmick. The pencil does have a triangular shape and a nice enough finish.
My thanks to blog reader Robert for sending me this pencil.