As you all may or may not know (or at least, will know now), chopsticks were first invented in ancient China about 4,000 - 5,000 years ago before spreading across the continent and essentially all of Asia. With the spread of this technology, the size, shape, and cultural functions differentiated slightly across ethnic boundaries. Chinese chopsticks tend to be longer as accustomed to the tradition of having lots of food on larger dishes that longer chopsticks are better for reaching. Japanese chopsticks tend to be the shortest due to the custom of bringing the bowl closer to the mouth when eating.
Korea’s own version of chopsticks were invented about 1,000 - 2,000 years ago. If Chinese chopsticks are long and Japanese chopsticks are short, Korean chopsticks tend to be (literally) of “medium” length and are the only ones made of metal. This originated from the chopsticks that the royal family used which were made out of pure silver. The silver would change color when it came into contact with poison serving a dual function of being aesthetically pleasing and protective. The people wanting to emulate the royals turned to metal chopsticks and the metal was thought to be more hygienic. Thus, today we see the modern stainless steel chopstick! Innovative!