Chinese letters’ difference in China, Taiwan, and Japan.
Today, Chinese characters are used by those three countries.
For example, Bei-jing is written “北京”, To-kyo is written “東京”.
Although pronunciation is different, 京 means city among three countries.

In 20C. China did radical full-model change to own characters.
Japan did small changes little by little.
Taiwan guarded tradition.
That is why at now,
Easy to write China > Japan > Taiwan difficult to write
this example is “library”
图书馆(CH) 図書館(JP) 圖書館(TW)
Yep, in these days, Chinese Chinese character is most simple 😀
There are street letters artists in China. They still write old style character like Taiwan.
Chinese letter in Vietnam and Korea
Vietnam used until 20 century.
(Their Chinese characters were already very different from original at old time. that was called Chu Nom.)
They changed to alphabet in 20C.
North and South Koreas used Chinese characters in old times.
In middle age, their king stopped Chinese character and made own characters.
They use Hanguel characters.