I spoke to a native of China last night who assured me that everyone in China knows the same meaning of flipping someone off as Americans.
When I asked about the origin, she said it came from the war between Germany and Poland.
The German soldiers pulled their gun triggers with this finger and a soldier in Poland said if they cut that finger off of every German soldier, they would win the war. When the Germans beat them, however, they showed that finger to say “Screw you, we won and we still have our gun trigger fingers.”
Great story but even if true, it can’t be the origin of the gesture, because it is described in much earlier times. Even the ancient Romans would have recognized the digitus impudicus insult, and that, of course, was before the invention and use of guns with triggers.
The finger is one of the most ancient insult gestures and was seen as phallic in meaning. The earliest attested reference to the finger comes from Ancient Greece when it was known as the κατάπυγον (katapugon, from kata – κατά, “downwards” and pugē – πυγή, “rump, buttocks”) and reference is made to using the finger in ancient Greek comedy to insult another person, where the term katapugon also meant “a male (or a female, katapugaina) who submits to anal penetration”.
In Ancient Roman writings it is identified as the digitus impudicus (impudent finger) and the widespread usage of the finger in many cultures is likely because of the geographical influence of the Roman Empire and Greco-Roman civilization. Another possible origin of this gesture can be found in the first-century Mediterranean world, where extending the finger was one of many methods used to divert the ever-present threat of the evil eye offense.
Here is another Internet rumor, albeit a bit earlier and with bows and arrows, about the one finger salute:
Before the Battle of Agincourt in 1415, the French, anticipating victory over the English, proposed to cut off the middle finger of all captured English soldiers. Without the middle finger it would be impossible to draw the renowned English longbow and therefore [soldiers would] be incapable of fighting in the future. This famous weapon was made of the native English yew tree, and the act of drawing the longbow was known as “plucking the yew.” Much to the bewilderment of the French, the English won a major upset and began mocking the French by waving their middle fingers at the defeated French, saying, “See, we can still pluck yew!”
Snopes says this is False. Again, the Ancient Romans and Greeks have the earliest and most documented evidence.