chessjoker

[Michel]

King+joker versus bare king. The ending of king+non-royal king versus king is an easy win, but if the joker is unable to deliver check (which is one possible interpretation of the rules you posted)

In this case whatever the rule is the joker would always be equivalent to a non royal king (the opponent has only one movable piece, a king).

I think you are alluding to a subtlety involving stalemate here. If you do not consider a virtual check (a check by a joker before the opponent moves) as a genuine check then there would be only statemate positions.

So I guess for the purposes of checkmate vs stalemate we should consider a virtual check as a genuine check.

[hgm]

The following rule seems to cover all cases:

For the purpose of determining stalemate and castling opportunity, it should be assumed that opponent Jokers continue to imitate the piece they were imitating on the preceding move.

[Evert]

The joker imitating king CAN do check!!!

Why should not?

So you keep saying. But how? If the joker's move-type isn't determined until after I've made my move, how is it threatening my king before I've done that?

I realise we're running into a bit of a language barrier here and the point is somewhat subtle, but it is important to get your rules unambiguous.

[Evert]

No Evert: In the case you describe, king CAN move in an open ray connecting to the black joker. We have to consider the situation with the piece released, at movement did: now the joker imitation is of a king and the check stops.

Ok (just to be clear: the question was somewhat rhetorical).
But then, what does it mean when you say that a joker "puts a king in check"? It clearly does not mean "if you do not move your king, take my joker or block the ray between them, I will take your king".

[Pippo]

I repeat:

1. Changes occur when the piece is released (like in FIDE).
2. Only in the castling are important the "passing cells" of the king (in other words, value of pieces not yet released). Again like in FIDE.

Conclusions: like in FIDE!

Assignment value to opponent joker is did at end of our movements. But that does not mean that its value "en passant" can affect in any way the game (as normally occur). EXCEPT IN CASTLING, situation peculiar also in standard FIDE.

[Michel]

But then, what does it mean when you say that a joker "puts a king in check"? It clearly does not mean "if you do not move your king, take my joker or block the ray between them, I will take your king".

It is a check in the sense that if the opponent would do a nullmove, you would take his king.

[Evert]

In this case whatever the rule is the joker would always be equivalent to a non royal king (the opponent has only one movable piece, a king).

Yes, obviously.

I think you are alluding to a subtlety involving stalemate here. If you do not consider a virtual check (a check by a joker before the opponent moves) as a genuine check then there would be only statemate positions.

Correct.

So I guess for the purposes of checkmate vs stalemate we should consider a virtual check as a genuine check.

Well, not necessarily: you can also say that these "virtual checks" have no real meaning. Both are possible interpretations of the rules as originally outlined, and as stated the implied rule s that the virtual check does nothing (because your joker's power is not determined until I move my next piece). What is not obvious is whether that is the intended rule, hence why I asked.
Now, I personally think (as I said) that the implied rule ("virtual check does nothing") is less complicated, and possibly also more interesting (it somewhat limits the power of the joker, mainly by robbing it of mate potential).

Alternatives could include that you declare stalemate a loss for the stalemated player, either always or when the other side still has a joker.

[Pippo]

No Evert: In the case you describe, king CAN move in an open ray connecting to the black joker. We have to consider the situation with the piece released, at movement did: now the joker imitation is of a king and the check stops.

Ok (just to be clear: the question was somewhat rhetorical).
But then, what does it mean when you say that a joker "puts a king in check"? It clearly does not mean "if you do not move your king, take my joker or block the ray between them, I will take your king".

I told you: if you don't like to call "check", call free as you like.
The important thing is that we are understanding the same game situation...

[Pippo]

The following rule seems to cover all cases:

For the purpose of determining stalemate and castling opportunity, it should be assumed that opponent Jokers continue to imitate the piece they were imitating on the preceding move.

Ok, it should be ok...

[Pippo]

But then, what does it mean when you say that a joker "puts a king in check"? It clearly does not mean "if you do not move your king, take my joker or block the ray between them, I will take your king".

It is a check in the sense that if the opponent would do a nullmove, you would take his king.

Right! Fine answer!