Ryō is a type of coin that was used a long time ago in Japan when mommy and daddy were not even born yet! It was a shiny coin and was made of gold or silver. People used it to buy things like toys, food, and clothes.
Just like how we use dollars to buy things, the Japanese people used ryō to buy things they needed. But ryō was very expensive and not everyone could afford it. Some people were very rich and they had a lot of ryō while some people were very poor and they did not have any ryō.
Nowadays, people in Japan do not use ryō anymore because they use a different kind of money called yen. Yen is like dollars but it has different pictures and is a different color. But some people still like to collect ryō and keep them as a special treasure because they are very rare and historical.