Guidonian hand
In Medieval music, the Guidonian hand was a mnemonic device used to assist singers in learning to sight-sing. Some form of the device may have been used by Guido of Arezzo, a medieval music theorist who wrote a number of treatises, including one instructing singers in sightreading. The hand occurs in some manuscripts before Guido's time as a tool to find the semitone; it does not have the depicted form until the 12th century. Sigebertus Gemblacensis in 1105–10 did describe Guido using the joints of the hand to aid in teaching his hexachord. The Guidonian hand is closely linked with Guido's new ideas about how to learn music, including the use of hexachords, and the first known Western use of solfege.
Hand cannon
The earliest reliable evidence of hand cannons in Europe appeared in 1326 and evidence of their production can be dated as early as 1327. The first recorded use of gunpowder weapons in Europe was in 1331 when two mounted Germanic knights attacked Cividale del Friuli with gunpowder weapons of some sort. By 1338 hand cannons were in widespread use in France. During the 14th century the Arabs seem to have used the hand cannon to some degree. Cannons are attested to in India starting from 1366. The Joseon kingdom in Korea acquired knowledge of gunpowder from China by 1374 and started producing cannons by 1377. In Southeast Asia Đại Việt soldiers were using hand cannons at the very latest by 1390 when they employed them in killing the king of Champa, Che Bong Nga. Japan was already aware of gunpowder warfare due to the Mongol invasions during the 13th century, but cannons were not mentioned until 1510 when a monk acquired one during his travels in China, and firearms were not produced until 1543, when the Portuguese introduced matchlocks which were known as tanegashima to the Japanese.