chessjoker

[Pippo]

until you don't move, my joker persists in the last imitation value. This is ok, it isn't?

It works, but you need to explicitly define it this way - and as I said, I think it's a mistake because it leads to very strange and counter-intuitive situations. In short, I think it makes the rules not be self-consistent.

Say I move my queen, then you check me with your joker. You say the joker still moves as a queen, therefore I am in check and need to do something about it. So I move a knight somewhere on the other side of the board. Now your joker moves as a knight, and therefore I am no longer in check. In fact, the only way I would still be in check (thus making my last move illegal) would be if I moved a queen (or rook, or bishop) in such a way that your joker still attacks my king - but then it doesn't matter at all if it was also moving as a queen on the last move.

Perhaps it only makes a practical difference in things like the KJvK ending.

Ex: my joker, imitating a bishop, is in front your king (for example: my joker is in b3, your king in b8 with no pieces between). It is your tourn: you cannot move the queen, neither a rook! This is what I call "inhibition"; it is very importan: if I attack your queen at next movement (with immutate situation joker-king) you lost your queen because she does not escape.

Is it clair now?

You cannot put yourself in check, that's obvious. But that isn't the situation I'm referring to.

All right Evert! I can stop a joker check simply moving another piece (includind the same king!). But I don't understand what kind of mistakes or conflits that it is able to produce: why? Example, please.

<<but then it doesn't matter at all if it was also moving as a queen on the last move>>

depends on you mean with "matter" . The only fact is that the joker-queen did check to the opponent king. You have to stop this check. Manner doing, could be simply, very simply or weird (in standard vision), but you have to do something as normally.

<<Perhaps it only makes a practical difference in things like the KJvK ending.>>

Here I don't understand what you say: sorry, my blame
What do you means with "KJvK ending"? For me is arabian
Sorry.

Ciao

[Evert]

I do not see why you consider this a problem. It is no different from a joker "attacking" a queen. The attack is only virtual since the joker will change into a different piece after the enemy moves.

It's different because there is no rule that says that I have to do anything when my queen is under attack. It affects things like KJvK (is it won or a dead draw?) and there is a subtlety with castling, as HGM pointed out.

So with respect to the king, it matters whether the joker's move changes at the end of my turn or at the end of your turn. I would find it most logical if it changed immediately (to "indeterminate") after the turn of the side whose joker it is, because after my the next move your joker would move differently anyway. You can play the game with either rule, but they're actually very different games.

Also consider the following example: White moves his queen, black moves a knight. Does black's joker still move as a queen? If it does, white cannot place his king on an open ray connecting to the black joker - despite the fact that he wouldn't actually be in check by doing so (provided the king is not next to the joker of course). Why? Apparently because there's a special rule that says so, but it doesn't seem at all logical or reasonable, given the rest of the rules.

These extra, somewhat ad-hoc, rules are really not a good thing. Of course traditional chess has them too (king not allowed to castle "through check") as do other variants (Shogi's convoluted drop rules with pawns, Xiangqi's convoluted chase rules).

[Evert]

depends on you mean with "matter" . The only fact is that the joker-queen did check to the opponent king. You have to stop this check. Manner doing, could be simply, very simply or weird (in standard vision), but you have to do something as normally.

In what sense did it check the king? This is a serious question. Does it threaten to take my king?
Answer: no, not really - unless I move a piece that would let it do so. But that would be the case independent of whether the joker would "have given check" before. It's more like a special type of pin than a check though.

Note that there is a difference here between delivering check (=your move threatens to take my king on the next move unless I do something about it) and leaving the king in check (=I make a move that allows you to take my king).

Here I don't understand what you say: sorry, my blame
What do you means with "KJvK ending"? For me is arabian

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)

[Pippo]

I do not see why you consider this a problem. It is no different from a joker "attacking" a queen. The attack is only virtual since the joker will change into a different piece after the enemy moves.

It's different because there is no rule that says that I have to do anything when my queen is under attack. It affects things like KJvK (is it won or a dead draw?) and there is a subtlety with castling, as HGM pointed out.

So with respect to the king, it matters whether the joker's move changes at the end of my turn or at the end of your turn. I would find it most logical if it changed immediately (to "indeterminate") after the turn of the side whose joker it is, because after my the next move your joker would move differently anyway. You can play the game with either rule, but they're actually very different games.

Also consider the following example: White moves his queen, black moves a knight. Does black's joker still move as a queen? If it does, white cannot place his king on an open ray connecting to the black joker - despite the fact that he wouldn't actually be in check by doing so (provided the king is not next to the joker of course). Why? Apparently because there's a special rule that says so, but it doesn't seem at all logical or reasonable, given the rest of the rules.

These extra, somewhat ad-hoc, rules are really not a good thing. Of course traditional chess has them too (king not allowed to castle "through check") as do other variants (Shogi's convoluted drop rules with pawns, Xiangqi's convoluted chase rules).

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.

This is, after all, the standard view: when you move a queen, you take care if she can check to the opponent king in the final position-cell or throw the all the passing-cells of the movement?

[Pippo]

The joker imitating king CAN do check!!!

Why should not?

[hgm]

In effect, change occurs when the piece is released.

OK. So if a black Joker is on d1, and white moves a Pawn (say h2-h3), and then black moves Jd1-d2, white can castle Ke1-b1, as c1, d1 and e1 won't get attacked by Jd2 until after the King is released on b1, right?

Fairy-Max now uses the (IMO more logical) interpretation that this is passing through check, because when it would move Ke1-d1, the King would be taken by Jd2 on the next move.

[Michel]

These extra, somewhat ad-hoc, rules are really not a good thing. Of course traditional chess has them too (king not allowed to castle "through check") as do other variants (Shogi's convoluted drop rules with pawns, Xiangqi's convoluted chase rules).

So far I have not seen a single case which is incompatible with "change happens on release". Maybe the correct rule should be: change happens just before the move is completed.

This would take care of the castling situations. Castling is impossible when in virtual check, or when passing through a virtual check. However you can castle into a (non-contact) virtual check since just before completing the castling move the joker will change into a king (yes I know there is a subtlety here since the king is supposed to move first but let's consider a castling move as indivisible).

[Pippo]

depends on you mean with "matter" . The only fact is that the joker-queen did check to the opponent king. You have to stop this check. Manner doing, could be simply, very simply or weird (in standard vision), but you have to do something as normally.

In what sense did it check the king? This is a serious question. Does it threaten to take my king?
Answer: no, not really - unless I move a piece that would let it do so. But that would be the case independent of whether the joker would "have given check" before. It's more like a special type of pin than a check though.

Note that there is a difference here between delivering check (=your move threatens to take my king on the next move unless I do something about it) and leaving the king in check (=I make a move that allows you to take my king).

Here I don't understand what you say: sorry, my blame
What do you means with "KJvK ending"? For me is arabian

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)

Maybe solution for you is simply do not call "check" in this case. Perfect! Really it forbides to move some pieces (and possibly some movements of some piece), nothing more.

Glad?

NOTE: a normal check also you can see as forbiding some movements and to move many pieces!!

But crucial point: a Joker can do check! Normally!

[hgm]

Does it threaten to take my king?
Answer: no, not really - unless I move a piece that would let it do so. But that would be the case independent of whether the joker would "have given check" before. It's more like a special type of pin than a check though.

I guess it is a design choice whether you consider a move as activating the opponent Joker(s) for the next turn, or as a way to turn off the moves they had before. In the latter interpretation passing your turn would not turn off anything, so your King would be captured after it. Unless you can actively turn off the Joker's King-capture move.

But I agree that actively changing the Joker's move does look a bit inconsistent compared to the rule that after a Joker move the Joker acquires the move of the piece the opponent Joker was imitation, rather than keep the moves of the piece it was imitating before.

[Pippo]

In effect, change occurs when the piece is released.

OK. So if a black Joker is on d1, and white moves a Pawn (say h2-h3), and then black moves Jd1-d2, white can castle Ke1-b1, as c1, d1 and e1 won't get attacked by Jd2 until after the King is released on b1, right?

Right Harm. If Fairy Max does differently, It should be correct.