Thank you for taking the time to read my comment.

I'm not discarding math as a tool to detect some problems that may appear in a game, but I wouldn't use pure mathematic to develop the game, because it may result in something that is 'mathematically correct' but not playable. I could, for example, use mathematical analysis, once I have finished my game, to check if it has errors of some kind. As for the rules that are 'forced' into a game, in order to 'fix' some inconvenience derived from another previous rule, maybe the problem is in that previous rule from which the inconvenience comes. You might find that one certain rule that you like very much provides more problem than benefit. Sometimes you can find some elegant way to elude the problem (and Fergus' example is simply perfect for illustrating this), but, there can be some cases where no appropiate solution is to be found, and then you have to remove your beloved rule and start from the beginning (this is painful but quite common when you begin designing games).

Not all the rules are valid for a game, and the fact that a rule is beautiful doesn't imply that it is suitable. I wouldn't prefer allowing players to force a draw by leaving their Galaxy on Hyperspace's black hole, instead I would check the rules about Hyperspace. Maybe some of the main rules of the game do not make much sense. Perhaps the error is in the fact that leaving your Galaxy in Hyperspace's black hole (which is such an easy thing to do) gives you such an enormous advantage. Somehow, it seems like you invented Hyperspace to let pieces be trapped on it, and later discovered that having trapped pieces was too great a disadvantage for one side and tried to fix it with another rule that overcomplicates the game and makes you have to introduce 3 more criteria to define a piece's impossibility to leave Hyperspace:

1. If a piece is not on the Black Hole's square, but is in hyperspace, and three or more moves have passed the next move of the player must be to move his piece onto the Black Hole, so long as the Black Hole square is not occupied.
2. If a piece has been in hyperspace for four moves or more, and is now on the Black Hole square in hyperspace, the next move of the player after the piece has entered hyperspace must be to move it to back to ordinary space, so long as a legal move exists that will let him do so.
3. If a piece has not made one of the above moves because it was not legal (ie: the Black Hole was occupied, or there was no legal move that permitted the piece to go back to regular space) the piece must make such a move as soon as it is legal.

This set of exceptions, and exceptions to the exceptions, and 'so long as'... is too much for me :)

PS: Please don't think that I absolutely dislike everything about your game. If you find my previous comments too harsh, you might feel glad to learn that there are certain aspects about Outer Space Chess which I do like sincerely, for example the way the 'Galaxy-Nebula system' (as you call it) works.

I appreciate the idea of a royal piece being a strong piece, and find quite interesting the way you achieve this by stating that only one piece may capture the Nebula, and then state that that piece (the Galaxy) cannot be captured (capturing your opponent's Galaxy would at least guarantee you a draw), but then, if you could find another way to reduce the Nebula's mobility, you wouldn't have needed to add the rules about:

-the Nebula not being able to move on 2 consecutive turns
-the Nebula not being able to move through 'attacked' squares, and
-the permission to capture your own pieces.

I'm just trying to provide a 'constructive review' with which, of course, you have the right to disagree.