The Chinese have been credited with many interesting inventions, not the least of which is fireworks. Fireworks entertain, excite, and intrigue people the world over at special events such as the New Year, religious festivals and, in the United States, the Fourth of July.
Fireworks are primarily a pyrotechnic devise with a low explosive level. The form of gunpowder used by the Chinese was made of saltpeter, charcoal, and sulfur dust. Bamboo shoots were filled with the gunpowder mixture and thrown into fires. The resulting explosions frightened away evil spirits during religious festivals. Some sources credit the Chinese with the invention of gunpowder, or black powder, by alchemists in the 12th century. Still others state emphatically that this mysterious concoction was first used in the 3rd and 4th century BCE. The Chinese called their invention huo yao or fire chemical.
The formula for the mixture of sulfur, saltpeter, and charcoal was a very carefully guarded secret. Its first recipe was written in code by an alchemist, Wei Boyang. Wei Boyang was also the author of The Kinship Of The Three, which is considered the earliest book on alchemy in China. In some of his writings, Boyang referred to the formula as using mercury and lead as the main ingredient of his gunpowder, rather than sulfur.
The Wujing Zongyao, written in 1044 AD, contains what historians believe to be the most accurate recipe for the early gun powder, or black powder. This first formula had potassium nitrate or saltpeter at 54.5% - 55.5%; sulfur at 19.4% to 26.5%; and carbonaceous or charcoal powder at 23.0% - 25.2%. This, of course, is the formula for the very basic explosive, not taking into account the layered structures which contained an inner ball of explosive, an outer coating, and an igniting paper. Mostly these were used in battle, but the same formulas, possibly in lesser degrees, were used to create the earliest fireworks.
It is still possible to purchase Chinese gunpowder fireworks through various websites. One which appears to have some interesting materials is Epic Fireworks out of England, and another is fireworks.co.uk. From either of these you should be able to find many Chinese gunpowder fireworks. Or, as a last resort, using the above formula you can create your own - taking all necessary safety precautions, of course.