That means that the Interactive Diagram isn't compliant with other rules of Apothecary. That said, I think that is fine. It is unreasonable to expect a simple "prototype" testing engine like the ID to enforce very nuanced rules exactly for all games. But I do think the question is not as clear as you make it out to be. If you add a Joker to Xinagqi, how does it imitate the King? Is it restricted to the palace? If it is not currently in the palace, can it move? Does it "check" the opponent king across an open file? Only in the palace?
Indeed, I don't worry about that. The purpose of the ID is not to provide an exact implementation of any particular variant. Just to provide a set of tools that makes it possible to get a fair approximation. And, as I said, this whole issue is a moot point. You could probably play hundreds of games before you encounter a situation where a Joker check would or would not make castling illegal or would checkmate or stalemate depending on this.
In general I don't think much of rules or rule complications that have next to zero effect on actual game play. I would always go for simplicity when it does not matter.
As for a Xiangqi Joker; this doesn't seem decidable by logic. It depends on whether you consider confinement as part of the move rules, or as an independent property of the piece type. Like the Joker would not mimic the royalty either, and can use a King move to step to an attacked square any time it wants. But of course you could make rules that would mimic any properties of the last-moved piece type.
Indeed, I don't worry about that. The purpose of the ID is not to provide an exact implementation of any particular variant. Just to provide a set of tools that makes it possible to get a fair approximation. And, as I said, this whole issue is a moot point. You could probably play hundreds of games before you encounter a situation where a Joker check would or would not make castling illegal or would checkmate or stalemate depending on this.
In general I don't think much of rules or rule complications that have next to zero effect on actual game play. I would always go for simplicity when it does not matter.
As for a Xiangqi Joker; this doesn't seem decidable by logic. It depends on whether you consider confinement as part of the move rules, or as an independent property of the piece type. Like the Joker would not mimic the royalty either, and can use a King move to step to an attacked square any time it wants. But of course you could make rules that would mimic any properties of the last-moved piece type.