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Rule Zero. A base or starting rule set for most Chess variants.[All Comments] [Add Comment or Rating]
Kevin Pacey wrote on 2020-12-20 UTC

In his Chess With Different Armies game, maybe Ralph Betza allowed promotion to one of the opposing army's piece types to try to add even more variety/excitement to some situations that might arise in actual games. However, it does seem more in the spirit of chess-like games (or perhaps even the CWDA theme) not to allow such an option.

H. G. Muller wrote on 2020-12-19 UTC


Benjamin Silversten wrote on 2020-12-19 UTCExcellent ★★★★★
I think it usually makes more sense to have pawns promote only to pieces in their own army.

Rodrigo Zanotelli wrote on 2013-03-30 UTC
Its usually said that pawn double step rule is to make chess faster.
On normal chess, there are 6 squares between pawn and promotion, and with those 6 squares between them, the double step rule is needed. 
With 5 squares betwen them it would not be needed or the pawns would be allowed to make the double step move after moving only one step on first move, to make the game faster.

Said that I think the double step rule should be changed to something like that:
"If there are 6 or more squares between the square that you are and the promotion squares, you are able to make the 2 steps move"

Well, this rule will fix most problems. But you will have problems if you play one variant where there are promotion squares at different distances (6 or more squares between the closest promotion square, 6 or more squares between the furtherst promotion square?).You will also have problems with variants where the pawn can jump or do something else that will make him move more than one square naturally (so, 6 or more squares between him and the promotion square? 6 or more moves between him and the promotion square? 6 or more turns [if you can move more than one time in a turn] between him and the promotion square?

Anyway I think this "variant" needs more rules: 
1-Castling is a move of the king or a move of the royal piece? (On my opinion its a royal piece move)
2-How check/mate works on a game with 2+ royal pieces? You need to mate only one piece to win? Mate both on same turn? Check/mates rules only take effect after there is only one royal piece on the team? Mate means enemy have no way to make all his royal pieces not be consecutively captured on next moves?
3-How promotion works? The piece that pawn (or another piece) promotes to is a new piece or a changed pawn? This would help to check if a royal pawn keep royalty and if the pawn moves go to the new piece (and so if the piece will be able to castle or not)
4-What happens when pawn start at a promoted square? Player promote before game start or on his first turn?

George Duke wrote on 2009-12-11 UTC
Aronson's Mad Scientist uses Rule Zero. 
Betza's Rule Zero should be revived to save verbiage. There are CVs of a 1000 words that could be 500 words. Actually good notation, some cross between a programming language and Bertrand Russell style logic system, would enable each CV to be fully defined in as many lines and characters as this comment without ambiguity. Then there would be more play.

Rich Hutnik wrote on 2008-09-07 UTC
I do applaud the effort here.  More needs to be done in this area.

However, I disagree with the pawn promotion rule.  Currently chess has a '9 Queen' problem.  It is theoretically possible in Normal chess for a player to have 9 queens.  The problem is that NO chess set provides you 9 queens.  This problem will get worse when you add variants.  Unless we want to have 'Jester' pieces who act as wildcards, and officially codify it in the rules (today a flipped rook in FIDE chess would be a Jester), the need for the rules and pieces to match should be dealt with.

I would recommend that whatever is the base rules, aka Rule Zero here, state that pawns can only promote to material that exists in the game, and accounted for my the rules, enabling players to also differentiate whose pieces belong to whom when promoting.  This is far more robust than the Rule Zero promotion rules.

I am interested in hearing someone argue against this, particularly when dealing with physical chess equipment.

George Duke wrote on 2008-08-31 UTCGood ★★★★
Betza's standard for 8x8, unfortunately much in abeyance.

Anonymous wrote on 2004-06-28 UTCGood ★★★★
Maybe this should include rules covering boards with holes, irregular edges etc.

Mike Nelson wrote on 2002-09-30 UTC
I still wonder about repetition=loss if stalemate is a win.  I can see why
this applies when stalemate is the only objective as in Nemeroth.  I also
use the rule in Separate Realms, where checkmate is the primary objective
and stalemate is a win because the nature of the pieces make mates

In reality, the rule has litte effect, but I have a couple of games on
file where avoiding repetition required one side to make an unsound attack
from a symmetric position and thus lose. In FIDE chess, the player could
and would choose to make the repetiton and take the draw. 

I think I prefer the latter outcome in these cases, but this is a question
of personal chess philosophy--while I deplore excessive numbers of draws,
I believe it is good that a very well-played game by both sides can end in
a draw. I can, however, understand and respect the opposite viewpoint.

Joseph DiMuro wrote on 2002-08-25 UTC
That should be Rook g8, Bishop f8, of course. (Man, what a brain cramp that was :-D)

Joseph DiMuro wrote on 2002-08-24 UTC
In response to the last comment:

[Is there any possible stalemated position where the illegality of
exposing one's King to check is not a factor?]

This is the simplest one I can think of: White King h8; White Rook h7;
White Bishop h6; White Pawns on e7, g7, and h7; Black King e8.

::::::::  (sorry for the ugly diagram)

White is stalemated, but not because it is illegal to move into check (the
king has no moves regardless).

Anonymous wrote on 2002-08-24 UTC

I would be interested in your reasoning on why repetition should be
forbidden if stalemate is an objective?  Does that also imply that the
50-move rule should be a win? (As you have stipulated for Weakest Chess,
changing it to 100 moves because of the weakness of the pieces.)

Taking these together, it does eliminate all draws, but is there a
necessary connection between stalemate=win and no draws? In Shatranj,
stalemate was a win but draws were possible. Modern chess changed
stalemate to a draw, perhaps with a view to punishing inferior endgame
play--many stalemates occur in positions where the stonger force could
have checkmated with better play.

Hypothetically, the primordial (pre-Chaturanga) chess had capturing the
King as its objective. Then players found the winning by oversight when
the opponent failed to protect his King against threatened capture or
exposed his King to capture wasn't rewarding, so the rules of check were
invented. A player could not expose his King to capture or leave it
exposed to capture, if he had any alternative.  Then the absence of moves
relieving the threat of capture was defined as the objective and the final
capture of the King was omitted--thus checkmate was defined. The absence
of alternatives concept is equally applicable to stalemate, in this case
the absence of moves which don't expose one's King to capture.  So by the
same logic, stalemate is a win--both checkmate and stalemate involve
taking away the opponent's alternatives to allowing his King to be

[Is there any possible stalemated position where the illegality of
exposing one's King to check is not a factor?]

gnohmon wrote on 2002-07-05 UTC
> [snip] Superko [snip] problematic [snip]

You are absolutely correct!

I have thought about it being problematic, but in the pressure of other
thoughts that have needed to be written down, I have not thought about it

Let me suggest this addition: 'In games where repetition is forbidden, it
may be difficult to see that the position has been repeated when the
repetition is not immediate. For this reason there must be a rule that
specifies what happens if a player mistakenly plays the forbidden move of
repeating the position.

First of all, in all circumstances there is no penalty and the forbidden
move becomes a legal move if the opponent fails to point out the repetition
before making a reply to the forbidden move.

When a forbidden repetition is pointed out, in a tournament game the player
who played the forbidden repetition has lost the game; but in a friendly
game, the offender is merely required to play a different move.'


JorgKnappen wrote on 2002-07-04 UTCGood ★★★★
I want to coment on the rule 'When stalemate wins, repetition of
is forbidden'. This rule is known to Go players as Superko rule. Alltho
it is implemented in some official Go rule sets (e.g. for New Sealand) it
is considered problematic. The reason is that humans are not good in
repeated positions except in the most simple cases.

In my opinion the FIDE rules are perfectly right: One can claim draw on
repeated position, but there is no automatic consequence.

A superko rule theoretically rules out a draw (or in Go terms: a no
but in chess there are just too many positions available to eliminate
effectively in play between humans.

gnohmon wrote on 2002-07-04 UTC
'Here is a proposed general castling rule' ... this is very good in its
way, but the real question is whether we want rule zero to get so big and
detailed. I'm not so sure, undecided, iffy, on the fence.

Rule Zero should be considered community property. It's not my personal
file or project; I kicked it off because we needed it, but from now on it
should be maintained and updated by consensus of the chess variant

Mike Nelson wrote on 2002-07-03 UTC
I agree with Ralph on castling--if his colorbound rule isn't sufficient,
the game designer should spell it out.  Here is a proposed general castling
rule for 'build your own army' type variants in which the designer can't
know what piece will be in the corner:

The King can Castle with whatever piece is in the corner, even though that
piece is not a Rook, and of course the usual restrictions and rules on
Castling apply. 

Definition: a 'possible square' for a piece is a square it could reach by a
series of one or more moves on an empty board, disregarding special moves
such as castling, pawn promotion, etc.

Castling kingside uses the first rule which results in the corner piece
moving to a possible square.
1. King to g-file, corner piece to f-file. (Normal castling)
2. King to h-file, corner piece to g-file.
3. King to g-file, corner piece to e-file.
4. King to g-file, corner piece to d-file.
5. king to g-file, corner piece to c-file.
6. King to g-file, corner piece to b-file.
7. King to g-file, corner piece to a-file.
If none of these rules apply, castling kingside is not allowed.

Castling queenside uses the first rule which results in the corner piece
moving to a possible square.
1. King to c-file, corner piece to d-file. (Normal castling)
2. King to b-file, corner piece to c-file.
3. King to a-file, corner piece to b-file.
4. King to c-file, corner piece to e-file.
5. king to c-file, corner piece to f-file.
6. King to c-file, corner piece to g-file.
7. King to c-file, corner piece to h-file.
If none of these rules apply, castling queenside is not allowed.

(The concept: if normal castling is not allowed, we try shortening the
corner piece's move and put the King next to it; if this also doesn't work,
we try lengthening the corner piece's move and put the King on its normal
castling square.)

gnohmon wrote on 2002-07-03 UTC
By the way, I never expected this page to get so many commnts!

gnohmon wrote on 2002-07-03 UTC
SBlkWlf says 'isn't fide rule zero enough?'

My answer is that I have been feeling the need for an extened rule zero for
quite a while. There are certain situations that have often arisen in games
that I have designed, and the resolution has often been to use the same
rules as some other familiar chess variant.

The rule zero file that I have written is biased towards the ingredients
that I have most often or most recently used in my own variants. Other
chess variant designers may prefer a different mix of ingredients, and may
wish to add some paragraphs to rule zero for this reason.

For example, I have always loved Cylindrical Chess; not so much as a game
to be played, although of course I have often played it, but rather as a
basic archetypical rule. One of the rules of Cylindrical Chess is that one
may not move a Rook (no other piece can do this) from a1 to a1 (via h1,
crossing the border). I also love a piece called the Rose, although I have
never played a game using one against a real opponent.

There is a rule that a Rose may not move from e1 to e1

I combined these in rule zero as a general principle. Nothing prevents you
from making up a game where every piece has some sort of null move and is
permitted to play it! the idea of rule zero is that usually the rules
should prevent null moves. Usually.

In fact, one of the benefits of rule zero is that somebody will make up a
game that violates everything in rule zero!

gnohmon wrote on 2002-07-03 UTC
Mike Nelson says 'The castling rule might not quite be sufficient.'

This is an excellent and well-considered observation. It makes me very
happy to see somebody new contribute such fine thoughts.

However, this is only intended to be rule zero. If you design a game where
you have a piece ADsNfbW which starts in the corner, you are expected to
notice whether or not Rule Zero gives an appropriate definition for
Castling with it.

Also, for example, I am currently working out a game where the board
contains 16 neutral pieces -- each of which covers a 4x4 area as in Grid
Chess -- which the players may move after their normal move, a multipart
move similar to Avalanche Chess. Rule Zero defines two things about this
game that I intend to specify anyway -- I intend to say specifically that
rule zero applies in two situations in order to avoid any possible doubt or

In this case, rule zero will serve not so much to save typing as to
reassure the reader of the game that the rules are familiar!

I have always tried to point out whenever possible that I am using rules
that are merely the standard FIDE rules extended by interpretation to cover
a new situation; for example, promotion to any piece (except P or K) in
either army (that's what happens in the FIDE rules, right?). And the reason
for pointing this out was to reassure the player that very few new rules
need be learned for the game.

(((of course, my last few games have been very much cucina bolognese, very
rich and with many ingredients; but hey, we go through phases in our

Mike Nelson wrote on 2002-07-02 UTCExcellent ★★★★★
The castling rule might not quite be sufficient. While it is simple enough,
there are some cases to consider:

1. The rule as stated is fine for a simple colorbound piece such as a
bishop. The bishop moves a-file to c-file -- a square of the same color
that it could reach by legal moves on an empty board.

2. What about an alfil starting on a1?  It could never reach c1--but it can
by castling. Similarly a wide half-knight (hN) on a1 could never reach c1,
even though it is not 'colorbound' (but can't reach all 64 squares).

SBlkWlf wrote on 2002-07-02 UTC
Sorry,  that would be more in line with Ji or Lawson's points, i should


SBlkWlf wrote on 2002-07-01 UTC
i don't know that this is really practical, or any more practical than
simply stating what specific rule changes from FIDE a particular variant
has on the page of it's original listing.  Isn't FIDE Rule Zero enough?

     Also, along the lines of Thomas's sugesstion, a more useful
compilation might prove to be a Zillions scripted Piececlopedia. 
Considering the wealth of work Ralph's done, surely by now most of the more
common pieces are presently defined in zrf terms somewhere.  Now THAT would
be a time saver!

    Instead of hunting through endless variants to see how a certain piece
might be defined, have all of them gathered in one file that could be
copy/cut/pasted from into a new variant.  We could even have a user rating
as to which specific manner of scripting a certain piece proved to be the
most effective; additionaly things like castling under all the variously
described conditions could be included also.


John Lawson wrote on 2002-07-01 UTC
You could define a handful of basic rule sets that would apply to most
chess variants, differing in such things as the effects of stalemate, or
repetition.  They could then be codified as Rule 0.1, Rule 0.2, etc., but
that rather defeats the whole purpose of a Rule Zero, which I understand to
be the irreducible minimum that most chess variants have in common.

It is also possible to say, 'Rule Zero applies, except for...'

Jianying Ji wrote on 2002-06-30 UTC
Then along these line one can establish a notation for describing 
the rule set of chess variants, in a similar spirit as Ralph Betza's
Funny notation for pieces. And if we have that, then we can have a
Funny variant notation to zillions translator, from that we can have 
a program that spits out random variants to play.

Whether this is good or not is in the mind of the bethinker

Tomas Forsman wrote on 2002-06-30 UTC
I don't know about any vast wisdom but on the top of my head I can think
about a couple of things you could add.
3d notation
tiles vs. points
winning by killing all or some of the other players pieces
winning by reaching a point on the board
pass allowed vs. not allowed
shared pieces
progressive turns

I'm sure you can think of more or find more by browsing around. I think the
idea is great and very usefull when making the rules for the site.
I hope you keep working on it.

With high respect and regards

Tomas Forsman

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