Chopsticks were developed about 5,000 years ago in China. It is likely that people cooked their food in large pots which retained heat well, and hasty eaters then broke twigs off trees to retrieve the food. By 400 BCE, a large population and dwindling resources forced people to conserve fuel. Food was chopped into small pieces so it could be cooked more rapidly, thus needing less fuel.
The pieces of food were small enough that they negated the need for knives at the dinner table, and chopsticks became staple utensils. It is also thought that Confucius, a vegetarian, advised people not to use knives at the table because knives would remind them of the slaughterhouse.
Chinese chopsticks, called kuai-zi (quick little fellows), are usually 9 to 10 inches long and rectangular with a blunt end. By 500 CE, chopstick use had spread from China to present-day Vietnam, Korea, and Japan.
(China.org.cn September 18, 2007)