Comments by João Neto

Hi Antoine

I wish to thank you to implement Slide Chess.

One problem: Each cage begins on the last player row, you must switch
cages in the setup (this is to avoid direct attacks to the enemy tower)

Hi, indeed Roberto got it right in his ZRF. 

The idea is that the remaining sliding square should not be at the
opposite edge (so, it will not go out of bounds). Both sliding squares
must be diagonally or orthogonally adjacent to the main 6x7 board. 

The last pushed square on the 6x7 board can have pieces, except a King.

Sorry about the wording, natural language can be though :-)

Joao Neto

The 1st point (check using a cage insertion) is correct.

However, the 2nd point may happen. A pawn inside a cage can be promoted by
an insertion. Check the comments in the game webpage.

Once again, thanks for your work on the ZRF :-)

I didn't understand the winning condition. How the game ends?

If the goal is stated in a sufficient abstract way, this may be a general
mutator for games with movement.

Even with Greg's extra rule, I think the game will create many passive
positions. You could restrict the switch option to non-royal pieces, so
the King could not switch (and so, couldn't easily escape eventual
attacks).

Also, check Swap Chess (www.chessvariants.com/diffmove.dir/swap.html) as a
similar CV concept.

That's a good idea. But it probably would mean that both players would try
to keep their queens near an adjacent piece, so they can create a new King
while demoting the previous King (if attacked) to a queen and escape the
attack. And this tactic could continue in a cycle.

Usually, I don't like this type of thing (ie, multiple Kings, demoting
royal pieces, ...).

Your rule seems appropriate. These original rules create too much havoc on
the position, and make medium-term strategies difficult to plan. 

At that time, I start playing a better variant of the same idea: Balanced
Swap Chess (http://www.chessvariants.org/diffmove.dir/balancedswap.html).
In this variant, the moving ability is much more constrained: only one
swap per move. 

Thanks for your comments! If you like to try a game of balanced swap
chess, email me.

David Pritchard's death is a loss (every death is) but his work on chess
variants is very much alive and, hopefully, will continue to be fruitful
for a long time.

I feel that chessvariants.org and its community of users (the only ones
that give some meaning to this collection of information) is a remarkable
tribute to his previous, pre-internet work, 'the Encyclopedia of Chess
Variants'. May our interest be a persistent thank you.