The caste system. There was also a fifth group, untouchables, who were considered casteless.
Beneficial generally means good, so I would say the way people were able to learn from each other. Realistically, the only thing the crusades did was kill people.
Great Britain and Japan are both island nations with limited resources. As a result, each nation developed according to its distinctive geographic location and limitations.
Both lands rose to become the two great pioneers of the modern world, but the biggest difference between them is that Great Britain had no role model to base its development on. It was the first industrial nation, it was at the forefront of the Industrial Revolution.
Both were isolated islands nearby the continent with limited raw materials to start the whole industrialization process. Britain had coal, iron and wool, but Japan had to import all these from another country.
Britain never has had a civil war nor domestic chaos, it was a stable nation and industrialization came in a more natural way. People in Great Britain started inventing steam engines, water frames and spinning jenny that helped the process to get started. They were motivated to move forward from hand production and agriculture and wanted machines and industrial companies.
On the other hand, by the mid-19th century, Japan was still a feudal nation under the authority of a warlord. The Meiji Restoration, in 1868, was named after the emperor who decided it was time to remodel Japan on a Western model and import new technologies. The goal was to make Japan a European-style empire that could compete in the increasingly global world. Japan had basically another way of thinking and the nation was pushed over the industrialization by foreign pressure.
The result was an industrial revolution that lasted from roughly 1890 to 1930. Factories were built, infrastructure was developed, and the Japanese economy quickly transitioned.
