It seems that most 3-D chess games are also weightless
chess games. Pieces (except for pawns) move up and
down with equal ease, the same as they do forward and
backward. They may be limited to diagonal only,
triagonal only, orthogonal and diagonal only, and so
forth, but none of the limitations (even with pawns)
seem to be related to gravity, weight, altitude, or
anything like that. Movement in any one direction is
as easy as movement in any other direction. It is no
accident that the oldest 3-D game still played is named
raumschach, meaning "space chess."

So it seems to me that when one goes to design a 3-D
chess game, one of the first questions to ask is "am I
making a zero gravity game?" It makes a big difference
if the knight has to *climb* to reach a higher level,
perhaps with the danger of falling, or if he simply
*drifts out* in that direction, free from weight,
falling, and all that other old-fashioned Earthly
stuff.

It seems to me that most attempts at 3-D chess are
zero-G games, and I like that. I'm a big fan of
zero-G. I run a Yahoo! group dedicated to nothing else
but sports in low-G and zero-G. In fact, I should put
a link from there to here, because while 3-D chess may
not be a SPORT, there's no denying that it is a GAME.

Of course, realizing this, I now have to wonder: are
there any 3-D but not zero-G chess games? Any low-G
chess games, whatever that might mean?