Once mixed, the hairs are again divided into small batches and placed on another machine that basically consists of a vibrating metal plate. Its motion straightens the hairs and ensures the tips are evenly positioned.

Next, in a step that sets Japanese brushes apart from those made in other countries, highly skilled workers use a traditional tool called a hanzashi to remove unwanted hairs, including ones that are facing the wrong direction or those that somehow have been cut in nature, giving them a blunt end. It can take five or six years for an artisan to master the hanzashi, which includes being able to feel which hairs should be removed simply by running a finger over the tips. At Chikuhodo, only three artisans in addition to Mr. Takemori are trained to use the hanzashi.

“All the brush makers who have been doing this for a long time have hanzashi,” Mr. Takemori said. “But according to the news around Kumano, many people don’t use them anymore. The reason for this is that, if the artisan doesn’t have very sensitive fingers, it can be dangerous to use.”

Mr. Takemori holds the hanzashi in his right hand, between his thumb and middle finger, and deftly maneuvers it along the hairs toward their tips, removing bad hairs between the blade of the tool and his forefinger. He says the number of hairs removed from any one bunch varies, but he estimates it to be around 20 percent. Once removed, the hairs are discarded and not used again.

Once the artisan has only hairs with soft, natural tips, it is time to shape the brush head. Mr. Takemori points out boxes and boxes of variously sized wooden cylinders, call koma, that are used as molds for the base of the brush head. He holds one in his left hand and, with his right, places the hairs inside the cylinder using a smooth twisting motion.

“We develop the shape and size of the brush heads together with the cosmetic companies, then make the cylinders here,” Mr. Takemori said. “By molding the hairs to a particular shape in this way, we avoid having to cut their natural ends, which makes the brush feel much softer against the skin.”