Knots of OBI Belts
Today, many variations of Obi (帯) knots are enjoyed in Kimono (着物) fashion.
Pic. 1 shows a gorgeous frill-styles for Furisode (振袖, long sleeved formal Kimono for unmarried woman). The Otaiko (お太鼓, square) style in the pic. 2 is for Tomesode (留袖, the most formal Kimono for married women) and Homongi (訪問着, formal Kimono).
There are many more kinds of variations, such as the ribbon style for Yukata (浴衣, summer cotton KIMONO) and Komon (小紋, daily type of Kimono). In fact, there were even more in the old time.
Originally, Obi belt was a mere narrow braided cord, and knots were made in front of the body. However, in the middle of the Edo (江戸) era, people began to make the knots at the back as the width of the Obi belt became broader.
As for front knots, I bet it remind you of Oiran (花魁, top-ranked Geisha) and Tayu (太夫, high-ranked Geisha). However, front knots were pretty popular among ladies from Daimyo (大名, feudal lord) clans, nobles, and upper Samuri (侍) families. Although front knots are very inconvenient to do domestic works, it was never a problem because those people had their servants. In Kyoto, front knots were also common among middle-aged wives of rich merchants.