Which of these is NOT considered to be one of the "Four Great Inventions" celebrated in Chinese culture?

While China has obviously contributed more than four inventions throughout history, the country celebrates four in particular as the “Four Great Inventions”, due to the developmental impact they had on the world as a whole: the compass, gunpowder, paper, and printing. When the four technologies were introduced to the Western world, they revolutionized civilization.

Compasses were first used in the 2nd century BCE. At that time, the invention was known as the “south-pointer”. It was primarily used for divination and fortune-telling until around 1050 CE, when it began being used for navigational purposes.

Bamboo and silk were initially used to record on, but bamboo was heavy and silk was an expensive luxury which could only be afforded by the imperial court. Paper as we know it was invented in about the year 105 AD by Cai Lun, an imperial court official. His paper was initially made of rags and other fibers, like mulberry and hemp. The new paper was lighter, cheaper and more suitable for writing on with a Chinese brush. Subsequently, a major revolution in the history of printing came along around 1040 CE, with the invention of movable clay type printing by Bi Sheng.

Gunpowder was inadvertently discovered by Chinese alchemists in the 9th century while they were attempting to develop an elixir for immortality. Although it was originally used for making fireworks, it was also put to military use as an explosive material for cannons, fire-arrows, and other weapons.