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Metamachy. Large game with a variety of regular fairy pieces.[All Comments] [Add Comment or Rating]
Daniel Zacharias wrote on 2020-12-29 UTCExcellent ★★★★★

Metamachy is fun. The historical pieces are all interesting to play with, and the fast pawns keep the game from slowing down too much.

H. G. Muller wrote on 2020-05-01 UTC

The key word here is 'common'. If a variant uses a concept that is unique to it, nothing is gained by moving its description off-page.

Anyway, I'd like to avoid language that use words of contested meaning that are a source of universal confusion. The current phrasing doesn't use any such terms at all, so there is no need to refer to anything for an explanation. Unless the new rule is that we can also no longer say things like "moves dagonally" or "moves like in orthodox Chess", but have to refer to the glossary item for Bishop for that.

Fergus Duniho wrote on 2020-05-01 UTC

I think it is a very bad idea anyway to refer to a glossary where the reader has to browse through several items with long and complicated definitions to learn something that could have been said in half a sentence.

For the sake of sharing a common vocabulary and avoiding disputes over the meanings of words on pages for individual games, we're going with the glossary. You are welcome to participate in the project of updating the glossary.

H. G. Muller wrote on 2020-05-01 UTC

capture zone - n. For a given piece, those squares on which it has the ability to legally capture a piece should the opportunity arise. This may include squares with nothing on them that it may presently capture. What matters is that if an enemy piece did move to a square, the piece could capture it. See threatened.

This is still no good. If the piece was pinned, he could still not legally capture an enemy piece that moved to that square. Unless you consider 'opportunity arises' to also mean "when it doesn't happen to be pinned, and when the that player is not in check". But then it could mean anything, e.g. why not "if there had been no pieces in its path blocking it", or "if it had been on a more suitable square". Involving vague, undefined concepts like 'opportunity' just makes things worse.

The FIDE rules do define 'under attack' as follows:


A piece is said to attack an opponent’s piece if the piece could make a capture on that square according to Articles 3.2 to 3.8.

3.1.3 A piece is considered to attack a square even if this piece is constrained from moving to that square because it would then leave or place the king of its own colour under attack.

It seems the definitions in the glossary have removed the reference to articles 3.2 to 3.8 (which we have to generalize here) and replaced it by the the term 'legally'. This is where the trouble starts, because 'legal move' in the FIDE rules already has a specific meaning (involving check), while what the FIDE rule meant to say here was "would conform to the rules of motion for the individual pieces" (ignoring check, which is only mentioned in 3.9). And we appear to be missing the all-important qualification 3.1.3 in the definition of 'under attack'.

I am not familiar with the term 'capture zone', but it seems you want it to mean "the set of squares that the rules for moving the piece (given the board population elsewhere, but ignoring any check rule) would allow it to capture an enemy on.

Note that the concept 'attack' in the FIDE rules only serves the purpose of formulating the check and castling rule, for which purpose captures that expose their own King are also valid attacks. It is never used in connection with non-royal pieces. This definition of 'attacked' therefore can deviate from the colloquial meaning as used by chess players, who will say things like "my Queen is under attack by a Pawn". It is IMO questionable if they would say that when the Pawn was pinned. But apart from what I think, far more serious is that the FIDE concept of 'attacked' is at odds with the definition in Xiangqi. There the rules do apply the concept 'attacked' to non-royals, in connection with the definition of perpetual chasing. And in this context attack on (or protection of) a non-royal always means "by a fully legal capture (recapture)". 'Attacks' by pinned pieces are not recognized as attacks. (Attacks on the King by pinned pieces are recognized as checks, though.)

Since we run a website for chess variants, I think it would be ill advised adopting a terminology that was exclusively defined in the narrow context of the 'FIDE rules of Chess', but would fail to be useful in other chess variants, amongst which the world's most played variant. FIDE rules should obviously not be binding for us, or the whole concept of a chess variant would be outlawed.

So I think the definition "has a legal capture move to the square when it would have been occupied by an enemy" would be the best definition for 'attacked', with the note that when applied to a royal, every capture would be legal. (Note that the FIDE rules also explicitly point this out when they use the word  'attacked' in 3.9.1 for describing when castling is allowed, while in fact this is redundant, as 3.1.3 already defined 'attacked' in that way!)

It can seem awkward that 'attacked' means something else for a royal then for a non-royal, and that a King would be 'under attack' on the same square where another piece would not be under attack. But in chess variants we have to deal with that problem anyway, as there might be divergent pieces that capture royals in other ways than non-royals. Again Xiangqi comes to mind, where the king attacks the opponent king through a Rook move, but not other pieces. And of course the Ultima Chameleon. It would solve a lot of problems if we distinguished 'attacks a square' (non-royal) from 'checks a square' (royal).

Note that these complications are a result of applying the concept in anticipation of a move, rather than to an actual position. In the latter case it would be obvious whether a legal capture to a given square is possible or not. But for judging legality of castling, it requires several fictions: that it is the opponent's turn, and that you have moved your King to the square in question. Without those fictions, f1 would not be under attack by a Pawn on e2, as 3.7.3 (to which the definition of 'attacked' refers) clearly states that Pawns can only make diagonal moves to squares occupied by an opponent. As we all agree that white castling is not allowed with a black Pawn on e2, we apparently agree that the rule must not be applied to the position before castling, where the Pawn had no move to f1. The FIDE rules do not specify whether the intended fiction (for the "square the King must cross") is that we should imagine (1) the King having moved there, (2) a second royal piece having been placed on that square, (3) a new non-royal piece having been placed on that square. Because in FIDE this doesn't matter. But in other variants it could. E.g. when there is a non-jumping Dababba on d1, it could not capture to f1 after (2) or (3), but it could after (1). I think the natural generalization would be (1): you cannot castle to g1 when you cannot legally move your King to f1.

That brings me to another issue in Metamachy: what if there is a black Cannon on f1, a virgin King on g1 and h1 is empty. Can the King now move to i1? In interpretation (1) it could, as keeping in the direct line of sight of a Cannon never exposes you to capture.

Anyway, while awaiting for you to make a final decision of how or whether to fix the glossary to make it conform to the Metamachy rules, I repaired the damage you had done to the Metamachy article. I think it is a very bad idea anyway to refer to a glossary where the reader has to browse through several items with long and complicated definitions to learn something that could have been said in half a sentence.

Fergus Duniho wrote on 2020-05-01 UTC

Regarding this particular edit, the rule has been made less clear.  I interpreted the glossary entry the same way H. G. did, so there is room for improvement.

I never meant that change to be the end of the matter, but I had to think a bit on how to revise the definition for capture zone. I have now revised it to use subjunctives and to explicitly distinguish between ability and opportunity.

Greg Strong wrote on 2020-04-30 UTC

As editors, we can and do edit content to bring it to a level of quality where we are willing to publish it.  Many of the submissions I review are of very low quality of writing.  They typically suffer from one or more of: poor grammar, poor formatting, inconsistent style, unclear rules.  If I am not sure of the rules, I ask for clarification.  Other edits I will often make myself to bring it up to sufficient quality, at least if I think the game is worthwhile.  It is not practical to engage in all the back-and-forth that would be required point out every mistake or adjustment that needs to be made.

Regarding this particular edit, the rule has been made less clear.  I interpreted the glossary entry the same way H. G. did, so there is room for improvement.

Regarding comments, I am seeing strong, confrontational language that I do not care for from multiple people.  It is essential - indeed required - that an attempt is made to be respectful.  I do not intend to go into details of which comments sepcifically, and by whom.  You all make valuable contributions to this site and I would like to see that continue.  And I understand we all become passionate at times.  But posters must be respectful.  Sometimes we just disagree and sometimes the correct answer, rather than digging in one's heels, is to let it go.  If it continues, I can and will start deleting comments.  Hopefully that will not be necessary.

Fergus Duniho wrote on 2020-04-30 UTC

I am shocked that you think you are at liberty to mutilate other people's contributions this way.

Since I didn't mutilate your page, you are shocked at something that never happened. But as the webmaster, I am at liberty to make any correction or improvement I see fit to make, and that's what I did.

And capture zone says:

capture zone - n. For a given piece, those squares to which it can legally capture.

This is not at all the case here. For one you cannot capture to a square that is occupied by a friendly piece; such a presence would block the move.

There is a can of opportunity, and there is a can of ability. Suppose you are in an empty room with no reading material of any kind. Can you read? Depending upon which sense of can is used, you can or you can't. You still have the ability to read, but in this circumstance, you don't have the opportunity to use this ability. The same kind of distinction can be made here. You have been focusing on the can of opportunity, but the can that applies here is the can of ability. In this sense, the spaces in the capture zone are those that a given piece has the ability to capture a piece on. Whether a piece has the opportunity to capture a piece on a space is a separate matter from whether it has the ability.

I am willing to tweak the definitions in the glossary, and that's what we can discuss now.

H. G. Muller wrote on 2020-04-30 UTC

Well, that is no good. The glossary says.

attack - ... 2. n. under..... The state of lying within the capture zone of an enemy piece.

And capture zone says:

capture zone - n. For a given piece, those squares to which it can legally capture.

This is not at all the case here. For one you cannot capture to a square that is occupied by a friendly piece; such a presence would block the move. Secondly, a piece that would be pinned to its King would not have a legal capture even on an enemy, as it is illegal to expose your King to check. While the Metamachy rules still forbid the King to jump over such a square. All this was discussed at the hand of examples.

In fact the definitions in the glossary agree exactly with what I have been saying all along, and which I supposedly 'misunderstood' in the description of Zanzibar-XL. It seems that you are the one confused about what the terms mean or what the Metamachy rules are. So in fact you have ruined the article by replacing an exact and concise description of the rules by an indirect reference that gets it wrong.

I am shocked that you think you are at liberty to mutilate other people's contributions this way. Even if I would have written something that was plain wrong, the proper procedure would have been to point out my error and ask me to fix it. Please change it back to how I formulated it!

Fergus Duniho wrote on 2020-04-30 UTC

I replaced the explanation of "under attack" with a link to the glossary.

Jean-Louis Cazaux wrote on 2020-04-15 UTCGood ★★★★

Thanks a lot. I didn't know about Lioness, very good.

H. G. Muller wrote on 2020-04-14 UTC

Oh, I see that this article article was actually written by me. I had completely forgotten about that. I now adapted it as you asked. I also added a note about 'Lioness'.

Jean-Louis Cazaux wrote on 2020-04-14 UTC

Could it be possible to remove now the line saying:

Some of the rules that were not clear from the original description on Jean-Louis Cazaux's website were derived by Fergus Duniho from the Zillions-of-Games implementation of Metamachy.

As soon as I saw it, I asked what was not clear and I have clarified the original description. 

Many thanks

H. G. Muller wrote on 2020-01-24 UTC

@Kevin: Human play is far from perfect, even for GMs. Misconceptions about piece values is just one of the contributions to imperfection. So, yes, GMs can have opinions, and the can afford these opinions to be wrong and still be at the top, because their competitors have their flaws too.

If the value of pieces depended on the general level of play, they would be meaningless concepts. We don't teach beginning chessplayers other piece values as those that GMs are using. Only if a player has a misconception applying to a specific piece, such as that knights are best moved to the board corners and should stay there, it can affect the value this piece has for them.

dax00 wrote on 2020-01-24 UTC

It's nice to hear different opinions. Perhaps I am somewhat biased due to the demolition work my Gryphon has done in the tournament game.

Greg Strong wrote on 2020-01-24 UTC

I also do not subscribe to formula.  I've been here long enough to watch at least a half-dozen well-thought-out systems be disproven.  The killer is that, not only has it not worked for pieces (e.g., the Archbishop is significantly stronger than anticipated), but also because it depends on the entire army (e.g., the individual pieces of the Nutty Knights aren't that strong, but together, they are totally overpowering.)

Regarding Griffon vs. Queen.  I am firmly in the camp that the Queen is better.  The case has been made that the larger board favors the Griffon - which is true to a point - but the difference is microscopic.  The Griffon suffers more in the corner or the edge, especially if blocked at the key points.  The larger the board, the fewer squares are edges/corners.  But the difference is small and the Queen and Griffon are active, attacking pieces that aren't likely to be there anyway.  Far more important is the fact that, while the Griffon has 8 rays, they emerge from 4 choke points where they can be blocked.  This limits mobility measurably.  Additionally, the Queen can slide along all 8 rays while continuing to attack the ray.  The Griffon cannot do this at all.  If it attacks even files, and makes a file-move, it now attacks odd files.  Same with ranks.  The result is that the Queen can triangulate - if it wants to attack a square, and is threatened and forced to move, it has several options of other squares to relocate to while still attacking the desired square.  The Griffon has a much harder time with this - for squares outside short range there is no option at all.  Also, it has problems with asymmetry.  One Griffon can attack another and the other may not be able to attack back because they follow different paths.  These sorts of anomolies do weaken peaces to some extent.  FInally, a Queen cannot be attacked by a King because it attacks all adjacent squares.  The Griffon can be approached.

All that said, the Griffon has some neat capabilities.  In particular, in the endgame, the ability to attack two files (or ranks) and trap the king between them is pretty good.  A Griffon plus a Rook is deadly.  Get the King betwen the Griffon's forks and then move the rook in between and that is checkmate, even if the King is in the middle of the board!  (When is the King ever checkmated in the middle of the board?)  So maybe, just maybe, a Griffon can be better in the very endgame, but I'm not even sure that is clear.  (King + Queen vs. King is much easier to carry out than King + Griffon vs. King, which is kinda tricky although still possible.)

I don't know the difference in value - a pawn sounds like a good starting point - but there is no doubt I will trade a Griffon for a Queen in even trade.

Kevin Pacey wrote on 2020-01-24 UTC

By coincidence or not, H.G., that's about 87% of a queen (on 8x8, at least) which is in line with the 85% ratio offered by the old ZoG article (for 8x8), as well as the 88% (if I read right) offered up by the Betza article. I didn't check everything he's ever written so as to see if Betza thought the ratio applied on all board sizes, though. Last night my own quick sketchy re-calculations came up with a 90% ratio for on 12x12 (at least), not too different, but I would be less confident if not comparing it to ZoG and Betza's percentage figures.

One thing calculations based on theory do have the advantage of is offering up something quick, if computer analysis has yet to be done due to awkwardness of board size, for example. Players can always take calculated (or even computer-generated) piece values with a grain of salt, and/or treat them as ballpark figures, everyone should understand that, at least for CVs that aren't much explored. There is also the question of exact board size/shape being tested, exact armies used in a starting setup being tested (and the exact squares the pieces start on, as Chess960 might even show). Not only that, but the strength of an engine being used for testing, IMHO.

Dax00 didn't so far offer up a way to numerically estimate the value of a piece like the Gryphon (on 8x8, or 12x12), but rather something that looked like opinion to me. That's fine, if a number can then be offered up as at least a guestimate based on it (unless one prefers to keep it secret). Aurelian has done a kind of calculation already, based on some sort of premise(s), so it seems for 12x12 he agrees with the conclusion that it's better than a queen for that board size - what his exact number for it could be, I don't know.

P.S.: Even the best human chess players still cannot agree on even the exact values chess pieces should have, computers be damned. The current world chess champion values a bishop slightly more than a knight on average, as is tradition for a long time. I may be an exception, in that I think a knight is almost fully equal to a B - and in my days as a young man I reached 2400 USCF chess rating, and nearly 2300 FIDE (later 2400 Canadian rating, in my early 50s). Some would say I'm still pretty weak, since I blunder badly now and then. :)

H. G. Muller wrote on 2020-01-23 UTC

@Dax00: I agree completely that calculatory methods for piece values are usually no good. They qualfy as 'fact-free science'. The known values of the six orthodox pieces can be reproduced by infinitely many numerological recipes, which can be designed to give arbitrary values for any fairy piece.

I therefore do always determine piece values in an empirical way, by having a computer program play games in which the pieces are pitted against a combination of pieces of known value, and measure their performance. Through such measurements the Gryphon turned out to be worth about 8.3 on 8x8 (IIRC), on a scale where Q=9.5.


Aurelian Florea wrote on 2020-01-23 UTC

In the early versions of apothecary chess I have done these caculations. A Griffin is a pawn weaker than the quenn on a 10x10.About the same results I got for a marshall.  But increased board helps the griffin! Dax is correct!

Kevin Pacey wrote on 2020-01-23 UTC

It seems upon re-checking, I made an error in my calculations for the Eagle's value, then reinforced that by reading Betza's article the wrong way. For now I'll go back and use a value based on the old ZoG article's exact ratio that's found between a gryphon (Eagle, here) and a queen, if only for the sake of providing a quick and dirty numerical estimate, even though it may prove to be too low later on (with much experience). The value of bent riders is something I hadn't tried to calculate on my own before.

P.S.: If I am now reading the Betza article right, he values a gryphon (i.e. Eagle) as worth 88% of a queen, which is almost exactly the value that the old ZoG article implies it has.

dax00 wrote on 2020-01-23 UTC

Where the Queen provides distributed pressure, the Gryphon provides concentrated pressure. Against reasonable play, where you expect your opponent to try to make his pieces work together (reasonable to assume pieces are relatively close together), I assert that the Gryphon is a better piece for pressuring the opponent overall. Even when kicked away, it can often still maintain distant defense. And the forking potential is massive.

I was never one to subscribe to a calculatory method of evaluating piece values, rather in favor of practical analysis through actual play. 

Even if I were to concede that a Gryphon is about a pawn less in worth than a Queen on an 8×8 board (which I do not), it makes sense that the Gryphon's initial diagonal move would mitigate its strength more so on the smaller board than on the 12×12 board of Metamachy, so for this game its value should be at least comparable if not superior.

Kevin Pacey wrote on 2020-01-23 UTC

Before finalizing my own tentative estimate for the value of the Eagle (quite a bit less than a queen), I read Ralph Betza's article on Bent Riders, in the Piece Articles section of this website. If I understood his writings right, I'd already arrived at a similar value to what his would be for the Gryphon (what is called the Eagle in this game), even though I used a sketchier form of calculation. However, Betza worked out his theories for piece values before people began to try to estimate fairy piece values with the aid of computers.

P.S.: In the Piece Articles section, too, the Article 'Who is Who on Eight by Eight' puts ZoG's value for a Gryphon only about a chess pawn's worth less than a queen, so quite a difference in value, although those are old ZoG values that need to be taken with a grain of salt in many cases.

dax00 wrote on 2020-01-23 UTC

Pretty sure I prefer the Eagle over a Queen. So much versatility.

Greg Strong wrote on 2020-01-12 UTC

Confirmed.  Thanks!

Fergus Duniho wrote on 2020-01-11 UTC

That's now fixed. The function was testing whether a rankname equalled a filename, which would always return false. It was supposed to compare the ranknames of two coordinates.

Greg Strong wrote on 2020-01-11 UTC

In my game here, I want to capture En Passant.  It does not show as a legal move, although if I tell it to make the move anyway, it does work.

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