An interesting question I hadn’t thought of! I did some digging and here’s an answer that I hope helps.

The earliest origin of the game we now know as “rock-paper-scissors” was in Ming dynasty author Xie Zhaozhe’s book Wuzazu (early 1600s). However, Zhaozhe themself also stated that the game originated even earlier, in the Han dynasty 1400 years earlier. In China, it was called “shoushiling.” Even so, I found very little information on this version. The game was then imported into Japan, where it became part of what was called “sansukumi-ken.”

The version imported from China was called “mushi-ken,” and it involved a frog (the player’s thumb), a slug (the player’s pinkie), and a snake (the player’s index finger). Frog beat slug, snake beat frog, slug beat snake. However, it is believed that there was a mistranslation, as the slug has been suggested to actually be a centipede. Even so, this was not the most popular version - that went to “kitsune-ken,” which consisted of a fox, a village head, and a hunter. The hunter kills the fox, the village head gets the hunter, and the fox kills the village head. Unlike how we know rock-paper-scissors now, kitsune-ken used both hands for gestures. In Japan, the current form of rock-paper-scissors appeared sometime in the Edo or Meiji periods - which gives us a time period of roughly between 1603 and 1912, though historians (such as Sepp Linhart in his 1998 work Ken No Bunkashi) believe it was within the 19th century.

We, however, should also consider the history of scissors. Believe it or not, the earliest scissors found originate from ancient Mesopotamia; they were bronze and had a flexible strip of curved bronze to allow them to close and release. It would not be until around 100 AD when the Romans developed what we would recognize as modern scissors (as in having a pivot point between blade and handle) with iron blades. Considering that this design eventually did make its way into Japan and surrounding areas in Asia, it would not be impossible for the two to be connected; furthermore, the name (particularly the variant “rochambeau”) is said to have some similarity to the Japanese name of “jan-ken-pon,” though I personally believe that’s a stretch

Regardless, rock-paper-scissors is believed to have reached America some time in the early 1900s, though when exactly also remains debated. The New York Times explains the rules in 1932 which suggests it was unfamiliar to a majority of people, but two novels from the mid-1910s mention the game in a way that suggests that readers would have known about it.

Regardless, it seems that while the concept of rock-paper-scissors has existed for well over 1800 years (or half the history of scissors!), the name hadn’t solidified itself as that until well into the 1900s. I hope that helps!