Followup: when/where were they invented and how/when did they spread?

"not discouraging more info on this topic, but FYI the use of chopsticks have been discussed in these previous threads", to quote a previous thread. Have you tried a search for the word "chopsticks" in this subreddit? I see

• Cutlery is popular in the West, Chopsticks are popular in the East. How did these utensils spread across cultures?
• Did precolonial India use western cutlery or chopsticks or something else? actually has some replies dealing with east Asia
• How did Chopsticks spread to so many different regions in Asia?
• In asia, how were chopsticks invented and chosen as a more practical eating implement than spoons and forks (which they also had)? NOTE: 79 comments, and it was posted 11 days ago
• Have chopsticks always been as popular in Asian cuisine, or did they replace another utensil?
• Why are chopsticks so prevalent in the Orient while Forks/Spoons in the West?
• Why did Asians start to use chopsticks but Europeans started to use forks?

Those are just the ones where the title looks most applicable (and I did look into the first half-dozen) and with the most responses.