I have copies of High Definition Copies of Hikaru no Go and I have begun cleaning and creating new version, and I have almost finished the first Volume...
but when I went through all of the raws I noticed that the last Volume - 23 has 64 extra pages in it and what I once thought was a complete series now has 2 chapters after the end and some extras and I am looking for a translator who can translate these last few chapter of an incredible manga, and I will do the rest.
If you want a taste of what is to come here you go!
search for hikaru no go chapter 190 .. are these the two extra chapters you are referring to? if they are... I think they came out some months after the series ended ... and since they dont really add anything to the canon if i remember right ... most people didnt pay much attention to them
I remember that there should be 2 extra one-shots coming out there after the manga ended. I only remember one of them where they show how Akira (that was Hikaru's rival right?) meets Hikaru. It ends with him sitting on the table or something. Long time since I read it.
The other I don't remember a lot of but it was either about Sai or Hikaru after the championship.