Yatsuhashi (meaning "eight bridges") is the best known meibutsu (regional specialty food) from the city of Kyoto, Japan.
The original yatsuhashi were thin, elongated cinnamon-flavored sweet crackers shaped like little curved bridges. The recipe for these sweet treats was extremely simple, consisting of rice flour dough, sugar, and cinnamon pounded thin, cut into long rectangles, and baked wrapped around hot iron rods (giving it its slightly rounded shape).
In later years however, this dough was used to make "raw yatsuhashi" (nama yatsuhashi), in which the dough was not baked but was instead lightly steamed to make a soft confection.
The final stage in the evolution of the yatsuhashi was to take the soft "raw" yatsuhashi and fold it into triangles around some kind of sweet filling. The original filling was of course the ubiquitous an (adzuki bean paste), but later all sorts of fillings were concocted, including chestnut, chocolate, strawberry, sweet potato, banana, etc.
In many cases, the dough of these modern yatsuhashi no longer even contains cinnamon, which many Japanese consider too "spicy", and instead is flavored with green tea, chocolate, salt, or other flavors.
Today it is these soft, triangular yatsuhashi, typically without cinnamon and filled with something super sweet that are the most common version available for sale on every streetcorner in Kyoto, although you can still find the original hard, crispy cinnamon-flavored little bridges if you are persistent.
Yatsuhashi were said to have been first invented by the Nishio family in Kyoto during the Edo Period, and there are records of the Nishios selling yatsuhashi as early as the 1600s. The name "yatsuhashi" was said to have been taken from an episode in the Tale of Ise called "The Eight Bridges of Mikawa", in which a mother's children drown in a river so she builds eight bridges in their memory.
For the Paris World's Fair of 1900, Nisho descendant Nishio Tameji was chosen by the Japanese government to travel to Paris and enter his family's traditional recipe for yatsuhashi into a competion of regional sweets. The confection won second place, an achievement which is still proudly proclaimed on boxes of Nishio-brand yatsuhashi to this day, along with the fact that they were the original inventors, in order to try to distinguish the Nishio brand from the numerous competing brands of yatsuhashi which have sprung up over the years.