There hasn't really been a log/forum/post on the "versus-ness" of single and multiple pieces goban. There are clear prices different, but there's no real "why". Some post I read says that multiple pieces of wood are MORE prone to warping, and then some said that they are LESS prone to warping. Some say that multiple are better, and some says nooooon. All the post out there currently are someone question on buying shin-kaya one piece or Hyuga-kaya multiple pieces, and everyone rush to say Hyuga kaya because of it's awesomeness and all that. And almost all of Kuroki goban(tabletop) that are hyuga are multiple piece board.
Some stuff I read on multiple pieces are pretty scary, splitting seam and color changes in individual piece of wood and all that.
So please, can some woodmaster clear this up once and for all (me, mainly)(But also those who would come after me too I guess)
By the way: What's the average weight of a 6cm board? I need to know to calculate shipping on several board I'm looking at now.