Everything's all scattered in regards to the much older imageboards... I find it kind of hard to find as a imageboard newb. I was interested previously in trying to write some vague history of 4chan on our wiki as part of our BBS culture, particularly when I realized w*rld2ch was connected to it, but i found it too overwhelming to invest the time into... (´人｀)
I'm sure it's trivial to find, just scroll through teh original SA thread long enough, but it's tedious..

on the topic of Hikari3, I don't quite remember how it started, but i know for sure it atleast had some roots in Heyuri. I can personally say syrno is connected to heyuri, i last saw him in a Cytube in i think late 2025, and a few times before that. We had them in our links page and i think had a banner up too, but i believe during their recent overhaul they forgot to re-add us. That got fixed recently though.

We had a chess tournament at some point that involved a bunch of BBSes (half of which didn't show up) and Hikari3 won, but i never added that to the page. I'll probably do it after this post.

One I don't know very much about is Kissu. I think it's been around for a while, but i have no idea how it came about, nor what it's been doing.