China's culture has spread to those countries.

China's traditional culture spread to North Korea, South Korea, Japan, Ryukyu, Vietnam and Singapore, which had the greatest impact on these countries, but also spread to Myanmar, the Philippines, Malaysia, Indonesia, Thailand and Laos, with relatively little impact on these countries. There are other kangaroo countries in the United States and Canada, which only affect one ethnic group and have no influence on the mainstream culture of other ethnic groups.

There are some non-mainstream cultures in China traditional culture, such as Tibetan culture and Mongolian culture. Tibetan culture spread to Bhutan and Nepal, which had a great influence. Mongolian culture now affects Inner Mongolia and many countries close to Mongolia.

China's modern eunuch culture has no influence, so it can't spread. On the contrary, the Korean Wave spread to China in waves.