Many of the traditional Japanese crafts make use of friction to keep its parts together.
A popular example of this is the architectural method called Kumiki (組み木) which constructs shrines and houses without the use of nails.
Yet, this is also true for clothing.
Kimono, when worn properly, maintains its silhouette by friction caused by the fabric used for the kimono and also the friction found within the sash(obi).
As you may already know, kimono doesn’t use a belt with a buckle to hold itself. In stead, it uses a special kind of sash(obi) to keep the piece together. While we do tie the sash from keeping it undone, the main force comes from the friction between the layers of the sash. That’s why some of the obi styles, such as katabasami 片ばさみ, works without making a knot.
And to gain the necessary amount of friction, we need surface area.
Much like the demonstration with two books, when wide surface areas are laired on top of each other, and are applied pressure, it sticks.
If the obi is twisted or not wrapped properly, it will easily get untied. Especially with koshihimo (腰紐), we usually just cross it and tuck the loose ends in, with out making a knot, so if its twisted, it’ll very quickly lose it’s effect.
