What was the idea behind simplification, given 行書 existed? Efforts of simplification of Chinese Characters predate the Communists by decades. I assume that all these native Chinese people in favour of simplification were infinitely  better educated than I am. While I use traditional characters, I have always thought it was obvious, why one might want some form of simplification: speed.

I further assumed it was clear why none of the existing scripts was chosen: we don't want to destroy the countability of strokes, that form the basis of the radical system!

Now, I looked a little bit into 行書 and was amazed! It appears faster on average than 簡體楷書  (perhaps this information is wrong?) and I can see  it has discernible strokes and radicals! Am I wrong? Why did people not promote 行書 instead of inventing a new 楷書-行書 mix?

Or was the goal memorability? I have tried learning both and found traditional characters more memorable. I started with simplified ones, so it definitely wasn't habit.

Or are there too many short radicals, making it hard to categorise them?



I am not proficient, so I can not use myself as the basis for comparing speeds. Today I even wrote an exam in 簡體  at half the speed of 繁體字，because I constantly had to stop the hand from writing 繁體字
Simplified Chinese is much simpler than 行書, involving less strokes overall. Two reasons:


Many simplified characters were already derived from cursive forms (草書楷化). Examples include 書 → 书, 車 → 车, 興 → 兴. 草書 is much less strokes than 行書.
Simplification involved many different techniques, including removing entire radicals or portions of a character, like 習 → 习, or even reconstructing the character based on new radicals, like 響 → 响. Therefore there's many more ways to reduce strokes than relying on cursive forms alone.


So 行書 wasn't used because it's not simple enough. There was an attempt to go even simpler during the Cultural Revolution, but it failed due to being too radical.

YMMV of course; it's possible that 行書 is genuinely faster for you than Simplified, but on average less strokes = faster handwriting, and Simplified is generally faster to hand-write than 行書. See also: How much faster is it to write Simplified over Traditional?