So how do you explain a diagonally forward move of a Castle can turnover, but neither move the entire Castle nor the Wall to an empty square?
Here is only my interpretation (can differ from what the inventor had in mind!):
"Last Castle", "Normal Castle attacked by enemy" and "Normal Castle not-attacked" are not the same piece and they should have different names.
The last Castle should be automatically promoted to a King who cannot move/capture diagonally forward, the entire King is moved and no parts of him (Betza notation WbF) and after the move this King isn't allowed to be in check.
A normal (not-last) Castle attacked by the enemy can (but is not forced to) move/capture like a King, but only to squares not attacked by the enemy. If the attacked Castle doesn't move at all and is captured, that doesn't matter
A normal (not-last) Castle not-attacked by the enemy can only use it's outer Wall (pawn) moves: either 1 or 2 squares forward if they are empty, or turnover with an own piece 1 or 2 squares forward or 1 square forward diagonal or capture an enemy piece moving like the above mentioned King (Betza WbF)
As mentioned, this is just my interpretation of the rules, it is not necessary the opinion of the game inventor, and probably not upto date with the inventor's latest rule changes.
For my taste, the rules especially for the "Castle", which is obviously the same name for multiple pieces with different move combinations, are way too complicated to be remembered and should be simplified if possible
Here is only my interpretation (can differ from what the inventor had in mind!): "Last Castle", "Normal Castle attacked by enemy" and "Normal Castle not-attacked" are not the same piece and they should have different names.
The last Castle should be automatically promoted to a King who cannot move/capture diagonally forward, the entire King is moved and no parts of him (Betza notation WbF) and after the move this King isn't allowed to be in check.
A normal (not-last) Castle attacked by the enemy can (but is not forced to) move/capture like a King, but only to squares not attacked by the enemy. If the attacked Castle doesn't move at all and is captured, that doesn't matter
A normal (not-last) Castle not-attacked by the enemy can only use it's outer Wall (pawn) moves: either 1 or 2 squares forward if they are empty, or turnover with an own piece 1 or 2 squares forward or 1 square forward diagonal or capture an enemy piece moving like the above mentioned King (Betza WbF)
As mentioned, this is just my interpretation of the rules, it is not necessary the opinion of the game inventor, and probably not upto date with the inventor's latest rule changes. For my taste, the rules especially for the "Castle", which is obviously the same name for multiple pieces with different move combinations, are way too complicated to be remembered and should be simplified if possible