What is Floss silk (Mawata)?

What Is Mawata (Silk Floss)?
— Silk Spread from Cocoons into Floss

Mawata (silk floss) is silk made by opening silkworm cocoons and spreading them into floss-like sheets.
Many people ask, “Isn’t mawata just cotton?”—but mawata is 100% silk, born from silkworms.
In Japan it has long been used for silk-floss duvets, kimono linings, and fine textiles.

What Is Mawata?
Mawata vs. Cotton: What’s the Difference?
How Mawata Is Made
Features & Appeal of Mawata
Examples & Ways to Enjoy
Hands-on & Workshops
Ethics & Circularity
FAQ

What Is Mawata?

Mawata (silk floss) is made by simmering cocoons to soften them, removing the pupa, then stretching each cocoon into thin layers and stacking them.
From these airy sheets, we hand-spin thread and continue the journey into woven cloth.

→ Read our post on hand-spun mawata yarn & silk floss

Mawata vs. Cotton: What’s the Difference?

Item	Mawata (Silk Floss)	Cotton
Source	Silkworm cocoon (silk)	Cotton boll
Fiber nature	Long continuous filaments	Short staple fibers
Traits	Light, warm, moisture-regulating, smooth	Durable, absorbent, everyday-friendly
Typical uses	Silk-floss duvets, kimono linings, fine textiles	T-shirts, denim, towels

Four Types of Silk Threads from Cocoons

From silkworm cocoons, four major thread types arise depending on purpose and processing.

Raw silk (reeled filament): Long continuous filament reeled from sound cocoons; historically used for kimono and even parachutes.
Tama-silk (from double cocoons): Taken from cocoons spun by two or more silkworms together; notable for unique thickness and texture.
Spun silk: Yarn respun from fibers taken from waste/irregular cocoons.
Mawata → Tsumugi (pongee) yarn: Cocoon is simmered and spread into floss (mawata), then hand-spun into a softly textured yarn.

Mawata in Everyday Life: A Brief History

From the Meiji and Taishō eras through mid-Shōwa, mawata was essential in daily life.
It warmed households as duvet and garment padding, and was given to celebrate a newborn. Light yet warm, mawata supported Japanese homes.
There was also a culture of using every cocoon—an embodiment of the “mottainai” (waste-not) spirit.

Properties of Mawata

Mawata consists of extremely fine filaments—often over a kilometer—entangled like a web, making it surprisingly strong and durable.
Because the micro-gaps between fibers hold ample air, it is light, lofty, and soft, with excellent thermal insulation that warms the body gently.

Appeal as a Natural Material

Silk’s main component, fibroin, has countless microscopic voids that absorb and release moisture.
As a result, mawata provides moisture absorption and release, staying comfortable and less clammy even in the rainy season or summer.
It also tends to resist static, helps absorb odors, and blocks ultraviolet rays.
Containing amino acids beneficial to humans and being gentle on skin, it is often comfortable for sensitive skin.

How We Make Mawata Yarn

1. Simmer the Cocoons (Pre-treatment)

→ How to Boil Cocoons
→ Blog: How We Boil Cocoons

2. Stretch into Mawata

We remove the pupa from the simmered cocoon, let it dry, then gently spread it into fluffy mawata sheets.

3. Hand-Spin into Thread

→ Spinning Thread from Mawata
→ Blog: A Gentle Guide to Hand-Spinning
→ Archive: Spinning Mawata

Features & Appeal of Mawata

Light & warm — Traps plenty of air, excellent insulation
Skin-friendly — Less static; comfortable for sensitive skin
Long-lasting — Silk-floss duvets and kimono can last for decades
Moisture-regulating — Silk’s natural moisture absorption/release

Examples & Ways to Enjoy

→ Mawata Play
→ The Story of Mawata

Hands-on & Workshops

→ Making Mawata with Guests — Like a Summer Holiday for Grown-ups
→ Workshop Information

Ethics & Circularity

At yamamayu, we waste none of the life received from cocoons.
・Pupae removed during mawata-making are composted
・Spent dye plants are composted as well
・Leftover yarns become “mottainai art”
Honoring nature’s cycle naturally leads to sustainability and an ethical approach.

→ Visit our Sustainability page

FAQ

Q. What’s the difference between mawata and cotton?
A. Mawata is silk made from silkworm cocoons; cotton is a plant fiber from the cotton boll.

Q. Why are silk-floss duvets so warm?
A. Mawata holds plenty of air, and its long filaments help retain heat—so it’s light yet warm.

Q. How should I wash/care for mawata items?
A. Wipe small stains gently; for overall care, air in the shade to release moisture.

Q. Any allergy concerns?
A. Silk is generally gentle and low-irritant, but sensitivities vary. If concerned, test on a small area first.