Hangul - Wikipedia

"King Sejong explained that he created the new script because the Korean language was different from Chinese; using Chinese characters (known as hanja) to write was so difficult for the common people that only privileged aristocrats (yangban), usually male, could read and write fluently. The majority of Koreans were effectively illiterate before the invention of Hangul.

Hangul was designed so that even a commoner could learn to read and write; the Haerye says "A wise man can acquaint himself with them before the morning is over; a stupid man can learn them in the space of ten days.""

Everyone thinks Chinese is hard. No wonder even the Chinese can't learn their own language:

Illiteracy Jumps in China, Despite 50-Year Campaign to Eradicate It