How many letters did Shang writing have?

It's difficult to give a precise number for the number of letters in Shang writing, as it was not a purely alphabetic system.

Here's what we know:

* Logographic: Shang writing was primarily logographic, meaning each character represented a word or morpheme (meaningful unit of language).

* Number of Characters: Estimates suggest there were around 3,000 to 4,000 characters in use during the Shang dynasty.

* No Alphabet: There was no direct equivalent of an alphabet in Shang writing, so we can't simply count the number of "letters."

* Evolution: The writing system continued to evolve over time, with new characters being created and others falling into disuse.

So, while there isn't a definitive answer to your question, it's important to understand the nature of Shang writing and its evolution.