Comments by Michael

I introduced the possibility of two rook castling for Latte Chess because
from playing against engines I found that the kings were getting stranded
in the centre files, and it was hard to manoeuvre the pieces into a position
to enable castling, without making their position worse (chess AI seems to have
little problems with this - however I feel that for us humans it could be
somewhat unpalatable). On the other hand I quite like the challenge of having to balance the desirability of castling with other pressing issues on the
board. I came up with two ideas that seem to be feasible for Latte Chess; these
being Luft Castling or Two Rooks Castling (or both together), being
available in addition to normal castling. Both seem to have pros and
cons. My problem with the Two Rooks Castling, in the context of Latte
Chess, is that it could make castling too easy. Luft Castling (in addition
to normal castling) seems more promising, as there is still some challenge
in arranging castling, especially as a piece must be moved to make space
for the Luft Manoeuvre. At the moment I feel that Luft Castling + normal castling seem the most promising solution, although at present I can't
find a way to test it!

I feel that experimenting with different kinds of castling for other
variants is definitely worth trying, and should be tailored for the
specific flavour and requirements of the variant. Tactical issues also
need to be considered. For example Two Rooks Castling introduces the
possibility of powerful double attacks on open centre (or near centre)
files.

Also, I have tried to find variant software to let me play against chess AI, but have been unable to find any that support this kind of feature. I would
be interested if anyone knows of any easy to use software for someone with
very limited programming abilities, so I can test these ideas? Thanks guys!

Thank you H. G. Muller for your input, I am always happy to receive feedback and ideas. The king double move to c2/g2 is interesting, however I feel that the king may not always be too safe on those squares, mostly due to the number and power of the bishops. e.g say the king double moves to g2, and then later the g2 and b7 bishops trade off. Now the king is rather vulnerable on g2, and whites queen does not want to get lured onto the a8/h1 diagonal, as blacks other white squared bishop might immediately spring into action.

Also I don't want to give up on Luft Castling just yet! I agree with what you said about the location of the rooks, but I have found through testing (without special castling) that the luft manoeuvre sometimes tends to happen naturally (manually). It seems to have some advantages, that would be even better if sped up. This is sheer luck, as I can now see that there was a distinct lack of sophistication in how I decided to include it as an option (i.e. "okay so let me find something that is like castling, but with an extra rook"!). It has the advantage that it immediately accelerates the development of 2 rooks, while moving the king to a safer place behind some wing pawns and the luft rook. It seems counter-intuitive, but somehow it seems to work, at least from my very limited initial tests.

I'm not discounting the double king move idea either though (I would prefer your first option - i.e. 2 steps to g2 subject to f1 OR f2 not being under attack). I feel it definitely needs to be tested along with the other ideas. And it could even be included along with luft castling and normal castling. I still have a lot of testing to do, which will be much easier when I can I find a way to modify an open source chess engine to include these features.

I've discovered that Sjaak II can be played in the terminal - which is
good for testing, and means that I won't need to modify XBoard.