Part 1.Why We Blend Brush Hairs: The Design Philosophy Behind BoBo Do Natural Hair Makeup Brushes

When I first began working on custom makeup brushes, I used to think mostly in terms of hair type.

Saikoho goat hair, gray squirrel hair, silver fox hair, Canadian squirrel hair, weasel hair, Kolinsky hair…

These names sound beautiful. For many natural hair makeup brush lovers, they immediately create certain expectations: softness, luxury, rarity, delicacy, or control.

But the longer I work with Japanese brush artisans, the more I realize that the name of the hair is only the beginning.

A truly beautiful makeup brush is never defined only by the hair it uses. It is shaped by hair type, hair length, density, brush shape, layering, blending ratio, bundling technique, and the artisan’s ability to bring all of these elements together.

This is why BoBo Do has become increasingly interested in mixed-hair makeup brushes.

A successful hair blend is not about adding a rare material just to make a brush sound more luxurious. It should solve a real design problem. It should make the brush softer, more structured, more durable, better at picking up product, or more suitable for a specific makeup style.

Koyudo considers hair selection one of the essential foundations of brush quality and explains that different animal hairs may be blended depending on softness, resilience, and intended use. Hakuhodo also notes that the characteristics of natural hair vary depending on the part of the animal and the processing method, and that the most expensive hair is not always the best choice for every makeup application. Chikuhodo similarly develops brushes by using the unique characteristics of each hair type.

These ideas are very close to how BoBo Do thinks about brush development.

I do not begin by asking:

“Which hair is the most expensive?”

I ask:

“What do I want this brush to do?”

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Softness Is Not the Only Goal in a Natural Hair Makeup Brush

For many of us, softness is the first thing we notice when we touch a makeup brush.

Softness matters. It matters especially for sensitive skin, delicate eye areas, and sheer powder application.

But softness alone does not make a brush truly useful.

A brush also needs pickup, release, resilience, shape stability, and a predictable sense of control when it moves across the skin.

This is why some extremely soft brushes feel beautiful to touch, but may not feel effortless in actual use. On the other hand, a brush with a little more structure and resilience may become the one you reach for every day.

When I test a brush, I always ask myself:

Does it pick up product easily?
Does it release too much product at once?
Can it blend without disturbing the base makeup?
Does it feel controlled, or does it feel too airy?
Does this softness actually serve the makeup result?

This is where hair blending becomes meaningful.

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Saikoho Goat Hair: The Structural Support of a Makeup Brush

Goat hair is one of the most practical and versatile natural hairs used in makeup brushes.

It offers softness, resilience, durability, and good product pickup. Hakuhodo describes goat hair as soft, resilient, durable, and suitable for powder, blush, highlighter, and eye shadow. Koyudo also notes that goat hair feels comfortable on the skin, lasts well, and is widely used for both face and eye brushes. Chikuhodo adds that goat hair has natural movement, airiness, and excellent powder-holding ability.

This is why goat hair, especially Saikoho goat hair, is so important in mixed-hair brushes.

It can bring:

• better product pickup;
• clearer color payoff;
• stable resilience;
• greater durability;
• stronger shape support.

When BoBo Do blends Saikoho goat hair with gray squirrel, silver fox, or Canadian squirrel, the goal is not to make the brush feel less luxurious. The goal is to make it more usable, more stable, and more suitable for daily makeup.

To me, Saikoho often works like the internal structure of a brush. It may not always be the most romantic hair name in the description, but it is often what makes a brush perform beautifully.

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Gray Squirrel Hair: Softness, Sheerness, and Sensitive-Skin Comfort

Gray squirrel hair is loved for good reason.

It has extremely fine tips and a silky skin feel, making it one of the most iconic soft natural hairs in Japanese makeup brushes. It is especially suited for soft, sheer, natural applications such as powder, blush, highlighter, contour, and eye shadow base.

Koyudo describes squirrel hair as having an excellent skin feel and good powder holding ability. It is suitable for highlight, cheek, shading, and eye shadow base. However, squirrel hair generally lacks firmness and durability compared with goat or weasel hair, and is best used with dry powder products.

This is exactly how BoBo Do understands gray squirrel hair in brush design.

Gray squirrel hair can bring:

• an exceptionally soft skin feel;
• lower irritation for sensitive skin;
• a sheer and natural finish;
• soft, diffused edges;
• a gentle experience for delicate skin.

But gray squirrel hair does not naturally provide strong structural support.

So when we blend gray squirrel hair with Saikoho goat hair, the purpose is very clear:

gray squirrel provides softness and sheerness, while Saikoho goat hair provides pickup, resilience, and stability.

This is one of the most classic and reliable approaches in natural hair brush blending.