8X8 refers to a now-defunct method of gaining skills.
In short, you got a boat, found a line that had no landmass, sailed slowly forward, cast a spell to find a place where you gained, and then move 8 tiles forward from that spot. It worked on land as well.
The 8x8 method was removed as a result of fixing the "streakyness" of the random number generater.
Currently, you can gain skills by simply standing in one spot.