filled with buckwheat
hulls instead of down
. Smaller and more dense
than regular pillows, and often shaped like a round bolster
rather than the usual puffy rectangle
. Sometimes flax
may be mixed in for a lighter feel. Originally from Japan
, source of so much elegance
Why? Like a beanbag, a buckwheat pillow comforms to your face/head/neck; unlike foam they tend to keep the shape you press into them, which some people find more comfortable. They also stay cool better than foam (and much better than down) and provide more support. Because they mold to any shape, they can help you sleep in cars, airplanes or other cramped places.
The Chinese apparently used to sleep with lacquered wooden saddles placed under the neck; a buckwheat pillow gives that sort of orthotic benefit without requiring you to sleep motionless.
Finally, if you apply a few drops of lavender and peppermint oil to the pillow (or a smaller one designed for the purpose) and place it over your eyes and brow, it can be a soothing palliative for headaches. That sounds really newage-y, but for some types of headache, it works.
Thanks Ereneta for clarification.