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Relativistic Chess. Squares attacked by the opponent are considered not to exist. (8x8, Cells: 64) [All Comments] [Add Comment or Rating]
Carlos Cetina wrote on 2012-07-24 UTC
OK. If no one else sees what I see, perhaps is due to I'm lost in the mazes of my mind.

Naturally, I will play according to the viewpoint of my opponents. 

Still have not received any reply from Kevin Whyte.

Fergus Duniho wrote on 2012-07-24 UTC
Again, I agree with Jeremy. I deny the existence of different virtual planes. Einstein's theory of relativity is not as weird as this. It is about differences in perceived passages of time, not in perceived outcomes. If one twin travels from the earth near the speed of light for what seems to him a short time, then returns at the same speed, he will find that his earth-bound twin has aged much more than he has. Both twins will agree that time has passed at different rates for each twin, resulting in different physical ages for each. Neither will have a virtual perspective from which his twin is still his own age. If one twin does imagine his twin as the same age as himself, it will be from delusion, not from relativity. Likewise, if one player takes the perspective that his King is not in check, it will not change the reality that it is in check. Different perspectives on reality are not equally valid. When one is true, other conflicting perspectives are false.

Carlos Cetina wrote on 2012-07-24 UTC
I knew about the existence of this variant in 2009 when John Smith launched an Open Invitation for playing it under the "Open Chess" name. I don't know why he picked out such a name instead of the original, more proper, "Relativistic Chess" name.

Played two games with him:

1) ultimatecoolster-cvgameroom-2009-314-878

2) ultimatecoolster-sissa-2009-353-907

I became fascinated with the variant and decided to work for making it more known. Thus, like a first step, invited to Nicholas Wolff and Jochen Mueller to playtest it.

CC-Nicholas Wolff

CC - Jochen Mueller

As a part of the divulgation, at July 19 posted a comment here in the Comments and Ratings section looking for to clarify the rules with the collaboration of the people in general.

I appreciate all the comments made here and am confident that among all those interested in this issue will finally find a consistent set of rules for this astonishing variant!


Jeremy Lennert wrote on 2012-07-24 UTC
The game has certain rules stating what moves are legal and what moves are not.  All the stuff about squares not existing is just a metaphor to help explain what moves are legal.  Unless you're arguing that we've misunderstood the rules and the pawn in that example isn't actually allowed to make a capturing move to the king's square (supposing for the sake of argument that there was a non-royal piece on that square), then any images or terminology you come up with to describe the situation differently is just window-dressing.

The goal of Chess is to capture the enemy king (all the stuff about check and mate is just legal boilerplate).  If you let me capture your king, you lose.

If you choose to envision the board in a way that implies that I can't capture your king--while simultaneously agreeing that, by the actual rules, I *can*--then you're just practicing an elaborate self-deception.  What matters (as far as victory conditions) is the set of legal moves, not the metaphor that describes them.

Carlos Cetina wrote on 2012-07-24 UTC
Quoting from my comment posted on July 20:

"We should view this matter like something that happens at two different levels or planes of reality: the first would be the "players level", a virtual field; the second, the true reality, that we all see as viewers, as spectators.

"Let's call them

"VP = virtual plane
"RP = real plane

"At RP the board is physically existent and formed by 64 squares that always are existent.

"At VP both players see two different things. Red sees that he is checking White's king; White sees that the pawn is not checking his king.

"Let's suppose h6 is empty, that is, White's king is not checked by any other piece.

"White's turn to move. Since he sees his king is not checked, he makes any normal move.

"Then comes Red's turn to move. Although he sees that his pawn is checking the king, he cannot make anything because in this variant the object of the game is to checkmate the advesary king, not to capture it; Red cannot force White to move his king from f3!

"What Red must make is with the participation of his remain pieces to put White's king in a position such that from White's viewpoint White's king be checkmated, such that White admits that condition."


Fergus Duniho wrote on 2012-07-23 UTC
What do RP and VP mean?

Carlos Cetina wrote on 2012-07-23 UTC
Right. 

I have no heard any comment from you about the metaphoric idea of seen this variant like something that happens at the same time at two levels.

The arguments you have been wielding hold and are quite valid at the RP.
The case we are analizing shows clearly the existence of the VP, that is, the relativistic concept of this variant.

The dispute is centered in the status of e4. It is inexistent for Red, existent for White's king [emphasizing ONLY for White's king not for his remain pieces]. This difference of viewpoints is a reality from the RP. We all that view the things from the RP must be fair with both players.

Speaking in general, we should state a rule for this variant that says something like this: if a piece with a ferz or wazir capturing range is distant from the opposite king two squares [on the RP], then the relation/situation among them shall not considered like check.

Therefore, in this only case we would have to accept the pretty weird case [as Jeremy says] that despite a player sees he is checking the adversary king, he cannot make anything. If we introduce a new category of checks, Red could say White: "cuasi-check" or "semi-check".

Fergus Duniho wrote on 2012-07-23 UTC
Whether you're in check depends upon how your opponent gets to move his pieces on his turn. This is the general rule in Chess variants, and we should not assume it is otherwise unless it is explicitly stated to be otherwise, which it is not.

Carlos Cetina wrote on 2012-07-22 UTC
If on d5 were placed a bishop or a queen instead of a pawn, from White's viewpoint would be check and White would be forced to move his king away from f3.

Do you see the difference?

Carlos Cetina wrote on 2012-07-21 UTC
I have just emailed to Kevin. Waiting for his reply. Sorry for we have been missing to the co-inventor Lee Corbin.

Christine: The ways of describing knight's move are 4 because also is possible one to the side then two orthogonally up.

Jeremy: to me also sounds pretty weird the fact that Red can not force White's king to move away from f3 [assuming h6 is empty]. I have no the guilt of things are different from the relativistic viewpoint. When one runs at a speed close to that of light it happens very weird things like the dilation of the time, lenght contraction and mass increase. But, of course, I shall adopt and fulfill the rules that arise from this discussion.

Fergus: Your inference, "it is only empty spaces that cease to exist when attacked" is very important. In the case of facing rooks, bishops or queens they are considered to be adjacent occupying existent squares, so the player to move may capture his counterpart.

Then, there are 4 persons agree [Christine, Fergus, Charles and me] in moving the knight like a true knight by dropping it directly to the (1,2) square if this is existent and, in the contrary case, to follow moving like nightrider until it lands on an existent square.

Christine Bagley-Jones wrote on 2012-07-21 UTC
Thinking about it again, the knight indeed could move 'again' as a knight, like a nightrider, but for the author not to mention this is bizzare. He is a troublemaker, hehe.

Christine Bagley-Jones wrote on 2012-07-21 UTC
Knight move, i mentioned 3 ways it could move, if you are trying to 'make a path', but of course, there is the way Charles said, being an action, a leap, and that is the way i see a knight move, and it could be that the creator of the game see's the knight moving like this also, therefore, the knight can only make a normal knight move, if legal.

I would be surprised if the knight could do a 'nightrider' type of move, though it is possible. especially seeing that it is not mentioned in the rules.  If the square a knight could move to does not exist, why should that mean that it can continue on moving again like a knight, wouldn't that mean it has actually 'used' the non-existent square?

You would think that if the knight had such a move, or a special way to move, he would of mentioned this type of move.  Seeing he did not talk about the knight, one could assume it only can play a normal knight move.

Fergus Duniho wrote on 2012-07-21 UTC
There are two ambiguities in the rules, both clarified by the example in which a Pawn can capture a Bishop. One is whether spaces occupied by your own pieces exist when attacked. In this example, the Pawn's space is attacked by the Bishop, yet the Pawn can still move. The other is whether the space a protected piece is on still exists. In the same example, the Bishop is protected by the King, yet the Pawn can still capture it. So it is only empty spaces that cease to exist when attacked.

Fergus Duniho wrote on 2012-07-20 UTC
Looking back at the earlier comments, I see that I'm in agreement with Charles Gilman.

Fergus Duniho wrote on 2012-07-20 UTC
I agree with Jeremy regarding check. The paradox he mentions can be resolved by distinguishing ordinary attacks from actual attacks within the context of the game's special rules. We may say that any space attacked by an enemy piece in the ordinary way, i.e. in the way it would be attacked if this were an ordinary game of Chess, does not exist for any non-royal piece the player may move. We may assume that the effects the current player's pieces would have on the ability of the opponent's pieces to move does not recursively feed back into determining which spaces do not exist. Otherwise, we could get endless loops and paradoxes.

With regard to check, it seems we should refer to actual attacks within the context of the game, i.e. it is check when a piece actually attacks the opponent's King.

With regard to the Knight, Nightrider leaping might make more sense. In Wormhole Chess, I specifically had the Chinese Chess Horse in mind as a model for how the Knight would move. But I don't think the creator of this game did. If we think of the Knight as a simple leaper analogous to the Pawn, we may do the same thing as we would for the Pawn. When the space a Pawn might move to does not exist, it moves to the first space in its path that does. Analogously, when the space a Knight would leap to does not exist, it might leap to the first space that does exist in a Nightrider path.

Jeremy Lennert wrote on 2012-07-20 UTC

Carlos, that sounds pretty weird to me. I think the spirit of the rules of Chess is that you really are trying to capture the enemy king, we just forbid moving into check to prevent games ending prematurely due to a dumb mistake; in variants, unless the intent is clearly otherwise, I think we ought to follow that spirit, which means "check" must be construed to mean "your opponent could capture your king next move". Playing on because white doesn't "perceive" the danger, and then forbidding black from actually making the capture because "the goal is to checkmate", seems to me to fly directly in the face of that spirit.

There's no reason you can't make a game that works like that, but inferring that as another designer's intent seems extremely implausible.

...

I think I see a potential for paradox in these rules. Suppose white pawn d3, black pawn d5. At first glance, both pawns seem to threaten e4. But that means that e4 doesn't exist for either player, which means neither pawn can move there. But that means that it isn't threatened, so it does exist...

Or you look at one side at a time, and say, for example, that white is threatening d4, so black can't go there, so black doesn't threaten it. Then there's no contradiction...except that you could equally well rule that black is threatening it and so white isn't! How do you decide between them?


Carlos Cetina wrote on 2012-07-20 UTC
I don't want to be considered like a stubborn, obsessed person. Your argument, Fergus, is precise and convincing. I'm about to admit it and to declare me as convinced; however there is something within my mind like an intuition that says me White's viewpoint is right [that is, his king is not checked by the pawn]. I'm doing an effort to state, to articulate said intuition.

If we admit the opposite viewpoint, where is, what is the relativity concept of this variant?

We should view this matter like something that happens at two different levels or planes of reality: the first would be the "players level", a virtual field; the second, the true reality, that we all see as viewers, as spectators.

Let's call them

VP = virtual plane
RP = real plane

At RP the board is physically existent and formed by 64 squares that always are existent.

At VP both players see two different things. Red sees that he is checking White's king; White sees that the pawn is not checking his king.

Let's suppose h6 is empty, that is, White's king is not checked by any other piece.

White's turn to move. Since he sees his king is not checked, he makes any normal move.

Then comes Red's turn to move. Although he sees that his pawn is checking the king, he cannot make anything because in this variant the object of the game is to checkmate the advesary king, not to capture it; Red cannot force White to move his king from f3!

What Red must make is with the participation of his remain pieces to put White's king in a position such that from White's viewpoint White's king be checkmated, such that White admits that condition.

We all that enjoy living at the RP what is what we see? The pawn is not checking the king.

Regarding the knight way of movement, as Christine points out there are three ways of describing it. Which of them we will choose? I'm definitively inclined to adopt the way that Charles suggested, mentioned at his first comment: to move the piece like if the action were a drop placing it directly on a square (1,2) away from the "origin square", regardless of whether the intermediate squares are or not existent.

I know this also raises a cloud of questions but we can go solving it gradually.

I'm going to email Kevin asking for his viewpoint. Searching by the Net I found his email address: [email protected].uic.edu


Christine Bagley-Jones wrote on 2012-07-20 UTCExcellent ★★★★★
Very interesting game, i have never noticed this before.
It appears to me the pawn is checking the King, and also attacking the pawn on a2.
It would be good to know what the author says about the Knight. Hans says 'The rules do not state exactly the way knights move. One could assume a knight moves one square orthogonally, and then one square diagonally, skipping again attacked squares.'
This is one way to describe the Knight move, but some people describe it as moving 2 squares orthogonally then 1 to the side, or even moving 1 diagonally and 1 orthogonally outward. If you assume it moves like Hans says, then it does appear it is checking the King.

Fergus Duniho wrote on 2012-07-20 UTC
A player is understood to be in check when an enemy piece could capture his King on the next turn unless he does something about it. That is the case with the Pawn and King here. The only perspective that matters is that of the player whose pieces are checking the King. If any could move to the King's space if it were his turn, the King is in check.

Carlos Cetina wrote on 2012-07-19 UTC
There are certainly similarities between RC and WC. The agreement that Nicholas, Jotchen and I have taken regarding the knight is to move it like in WC; then I agree with the knight on h6 is checking the king.

The fine point of the matter is the case of the pawn on d5. What you say,  "the rules only specify that the King is exempt from the rule that attacked spaces don't exist for pieces, not that it's attacks on spaces do not make them non-existent", is exact but it does not refute White's argument.

There are two opposite arguments:

1) From Red viewpoint it's check because e4 is inexistent;

2) From White viewpoint it's not check because e4 is existent.   

Like an arbiter, I would give the reason to White because the status of the board [regarding existency or inexistency] is changing move by move; after Red move 22... fxd5, White faces a NEW situation in which he sees there is an adversary pawn placed on e5, and sees there is an intermediate square between that pawn and his king. In other words, is the viewpoint of the player to move will determine the legality or illegality of a given move.

Fergus Duniho wrote on 2012-07-19 UTC
The rules explain that attacked spaces still exist for the King, because otherwise it would be too difficult to checkmate the King. This consideration does not go the other way. Making the spaces the King attacks non-existent to the opponent's pieces makes the King easier to attack, which makes the game more decisive.  Moreover, the rules only specify that the King is exempt from the rule that attacked spaces don't exist for pieces, not that it's attacks on spaces do not make them non-existent. With this in mind, I would say that the Pawn and Knight (assuming it moves as a Knight in Wormhole Chess) are both checking the King. The rules written here recommend the same movement used in Wormhole Chess, which this game has similarities to, and given the similarities, the same movement seems reasonable.

Carlos Cetina wrote on 2012-07-19 UTC
Fergus,

I would like to know your opinion about this variant. I find it interesting enough but feel the rules need some clarification.

I'm playtesting it with Nicholas Wolff and Jochen Mueller. With both have rise to some differences of interpretation in some points.

If we [all those involved in playing and studying CVs] do not get a consensus on its rules, will we declare it unplayable?

If it is playable, it would be possible to enforce the rules to the preset?

Why this variant is not more known and popular?

The following position correspond to the game I'm playing with Jochen.

White to move. 23rd turn.

1) Is the pawn on d5 checking White's king?
2) Is the knight on h6 checking White's king?

Nicholas, Jochen and me have agreed in moving knight first one orthogonal step followed by one diagonal [outward] step. If the passing by orthogonal square were inexistent, the knight will follow moving orthogonally to the next existent square; if the landing diagonal square were inexistent, it will move to the next diagonal [outward] existent square.

This way of movement differs from the mentioned by Charles Gilman in his first comment, where the knight would move like nightrider if the square (1,2) away from the starting one were inexistent.

Both ways are logical and playable... which of them we will choose as the legal? Which we will consider the best, the most reasonable?

Regarding if the d5-pawn is checking to White's king or not, my opinion is that not. From the Red viewpoint it's check but from White's does not, because for White e4 is existent and therefore the [capturing] action of the pawn does not reach to f3.

Thanks Kevin Whyte for putting our neurons to work!

Christine, Joe, Charles (Gilman), Hans (Bodlaender)... what do you say?


Charles Gilman wrote on 2009-11-11 UTC
Surely the rule is that if a square is guarded, according to the rules of FIDE Chess, by the player who has just moved, the player who is about to move cannot move to that square but just passes through it. A square need not be guarded according to the rules of Relativistic Chess itself. Therefore there is no ambiguity. It is the player about to move who cannot move their piece to that square.

Anonymous wrote on 2009-11-06 UTC
I found a paradox. If a knight is on d7 and a pawn is on d4, with nothing
preventing either from moving to c5, a paradox results. If the knight can
move to c5, then the pawn can't. If the pawn can, then the knight can't.
There is no way of detirmining who can move there in the rules, but try
these:

black gets priority
both can move
neither can move
the square and both pieces fall into a wormhole and vanish
creating this situation is an illegal move

Charles Gilman wrote on 2004-03-08 UTCGood ★★★★
Surely the rule for a Knight is that if a normal destination square is attacked it just continues as a Nightrider until it reaches a non-attacked square.

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