Comments by panther

I managed to make the Setup's 4D diagram for this submission appear normal, as far as both the 2D mini-board checkering patterning and having a thinner spacing for the inner margins between these boards. The trick I finally came up was to use a complex checker pattern that was to be generated by the Diagram Designer. For it I used two sequences of 29 binary numbers (i.e. 1s or 0s), plus I more or less alternated these 29 digit numbers a dozen times. It seemed excessive, but I didn't succeed with other ideas that I tried.

Hi Charles

I've read parts of the Game Courier documentation (much of which is
applicable to the Diagram Designer, from where the documentation can also
be accessed). The part that's devoted to FEN notation, I seem to recall,
mentions handling piece images that use multiple letters to be represented
in the FEN string. For a single piece that uses multiple letters, e.g. for
a (White) "Rocket" it could be represented in FEN in a piece set by RK;
simply use {RK} instead of entering a single letter (if you actually could)
in the FEN string for the chosen piece type. Hopefully an editor will help
if I'm not clear on this.

Kevin

Fergus wrote:

"This is now fixed. The "Alfaerie: Many" set wrote the $flipped array
itself, but drawdiagram.php reset the $flipped array before calculating it.
Stopping it from doing that fixed it."

One of my submission diagrams was affected, as I had previously taken into
account the (former) problem with that particular piece set. After the fix
by Fergus, today I simply switched the Upper & lower case letters I used to
represent the White & Black pieces, in my Diagram Designer generated
diagram.

It would seem anyone else who may have used that particular piece set
should check their diagrams as well.

Here's a diagram for the setup position of a possible variant idea that I'm playing around with. I'll post it here so I can study it at leisure. I was thinking that the (mann-like) pieces would move as in my Super4*Chess variant, and the pawns would move as in Tess Chess. The main idea would be to hope for better chances of a relatively early mate (perhaps even sooner than say Tess Chess might allow), or to hope for at least a relatively shorter game than other 4D variants might allow.

[edit: I've since rejected submitting this idea for a variant (it might have been called "Open King 4*4D Chess"), since it scores poorly in my estimation on allowing a variety of piece type exchanges, due to a lack of 'minor pieces'. In particular, there's no way to evenly trade a piece for a small number of pawns, kind of like as in a pure major piece chess middlegame. Plus, kings can only legally attack pawns, kind of like as in a pure queen endgame in chess. Perhaps someone else can do something with this sort of idea for a variant, though, or they may like it as it is anyway.] [edit2: I'm finding myself revisiting this idea now & then]:

Does anyone know if actual multi-opponent (i.e. 3 or more player) games are permitted by Game Courier (and if so, please confirm my guess that they are not permitted to be rated games by Game Courier's rating system).

I've spotted the odd 4 handed partnership variant as having been played on Game Courier, but it was always the case that just two players were playing, with each player controlling two of the four armies at the start of the game.

My answer would be basically the same as H.G.'s, including the spelling of
the link that he gave, given that I've never visited Ebay before.

I have a hypothetical question. If I would like to make an invitation for an opponent to play the variant "Chaturanga - Four Kings - Double Mate" against me, I seem to be faced with a slight problem. At the moment there seems to be just 1 preset for any sort of 4-handed Chaturanga (as played by two players on Game Courier). Though that preset is not rule enforcing, it also does not seem to provide a way to alert in advance anyone who might accept such an invitation that I would wish to play that particular version of 4-handed Chaturanga (i.e. "Chaturanga - Four Kings - Double Mate").

The only way to alert any potential opponent in advance of my intended choice of Chaturanga variant would, at the moment, seem to be for me to contact a particular person in advance, or wait for 1 (or more) person(s) to reply to a public comment I make, say, on chessvariants.com (such as this comment), and soon after for myself (or them) to issue them a personal invitation for us to play. Would that indeed be my only option at the moment so as to alert any potential opponent?


FYI, here's a link discussing this variant of 4-handed Chaturanga:

http://www.chessvariants.com/index/msdisplay.php?itemid=MSchaturangafour

Testing, to see if my comment shows.

(I posted two comments late last night, neither showed up, though strangely
it was indicated on the website that someone had just made a fresh post
each time that I did. I didn't need any HTML tag, either)

[edit:

I had included the following link:

http://www.chessvariants.com/index/msdisplay.php?itemid=MSchaturangafour

to show a particular Chaturanga variant ("Chaturanga - Four Kings - Double Mate"). I had wanted to say there seems to be only one preset (with no rule enforcement) that is used for if playing any of the 4-handed Chaturanga variants (i.e. to be played by 2 players on Game Corier). 

Hence, if one wishes to alert a potential opponent to one's desire to play the exact variant "Chaturanga - Four Kings - Double Mate" in advance of them accepting an invitation, they seem to be needed to be contacted in advance (such as via a public comment, like this one) prior to arranging any personal invitation using the 1 existing preset for 4-handed Chaturanga. Someone please point out to me if there is another solution in such cases of there being just 1 existing preset for more than 1 variant of a game.]

I may be wrong, but so far I've concluded that in Circular Chess there are possible mating positions with a K & 2Ns vs. lone K, or with a K & B plus N (or an opposite coloured B) vs. lone K, but it seems that they are not forcible, or 'basic' mates (unlike K & Q vs. lone K or K & R vs. lone K). Also, I'm guessing that a K plus some combination(s) of 3 minor pieces (aside from 3 same coloured bishops) may be able to force mate against a lone K.

Here's a link to a published preset for a Capablanca Chess style circular variant:

Circular Capa Chess

If I understand the up-to-date rules of Hyperchess4 right, a K & two Bs can force mate vs. a lone K. It is pleasing that this is the case in Hyperchess4, since in the classic Raumschach (a mere 3D, as opposed to 4D, variant) there doesn't seem to be any forcible 'basic' mate in the case of K & any combination of 2 pieces (excluding Qs or Ps) vs. a lone K. 

On the other hand, it could take getting used to that a K & Q can't seem to force mate vs. a lone K in Hyperchess4. Plus, as in most (if not all!) 3 or 4D variants, it seems that a King & Pawn vs. King wouldn't win nearly as often as it would in standard chess (in the case of Hyperchess4, I suppose it would quite rarely be a win, given that a K & Q cannot seem to generally force mate, at least unless the lone K is already "Held" by the superior side's K in the same 'big square').

Still, given that at least some 2-piece combinations can force mate vs. lone K in Hyperchess4, all it might take is to be just 2 pawns ahead in material to often win a game with good play thereafter, and this does not necessarily require that the opponent always play that badly before that stage. On this count alone, I'd think that Hyperchess4 is a pretty decent 4D variant.

In TessChess it's nice that there are mating positions that exist for just K & 2 non-Q pieces vs. lone K (so far I've spotted them for K & 2Rs vs. K, K & 2Bs vs. K, K & R & B vs. K and K & B & N vs. K, but mate with K & R & N [or K & 2Ns] vs. K seems impossible even with help), though it would seem at first impression that these are not forcible or 'basic' mates. In this way it's similar to the classic Raumschach, which is merely a 3D variant (as opposed to 4D). It's also similar in that K & Q vs. lone K is a 'basic' mate here, which is desirable, if not expected, in a variant meant to be not far from standard chess. As in most, if not all, 3 or 4D variants, it's the case that a king & pawn doesn't win as often vs. lone king as in standard chess.

In spite of the apparent strength of the the B & R in TessChess, compared to their counterparts in standard chess, in the setup position IMHO the 2 Ns remain as 'minor' pieces, which might be later exchanged on relatively even terms in some instances for a low number of pawns, useful both for making the game potentially more interesting, and practically, in that some menacing pawns might be dealt with in a way that may otherwise be almost always far too costly (say in an endgame or middlegame race situation involving connected passed pawns). Speaking of trades, originally I estimated that in TessChess a B+R+P might be worth a Q in some cases, but upon reflection I suppose it would almost always be preferable to have the Q.

I would rank what TessChess is to 4D chess as no worse than what Raumschach is to 3D chess, in terms of overall merit.

[edit: My tentative estimates for the relative piece values in TessChess are: P=1, N=3.4, B=5.6, R=7.4, Q=14 and a K has a fighting value of 10 (noting it can't be traded.]

H.G. wrote:

K.Pacey> in Raumschach there are possible mating positions with a K & B plus R

"How do you envisage that? Even in a corner the bare King can only be limited to a plane, and the other pieces would have to cover 4 squares in that plane (including the one the bare King is on). A Bishop could check and cover one of those at the same time, but the only way for a Rook to cover the other two would put it in a place that blocks the Bishop from checking.

I think you need at least two Rooks to have a mate position. And I am not sure that is forcible."

Hi H.G.

I imagined the lone K in a corner on the upper level. The superior side's K would be in opposition to it on the same file (say), same level. The superior side's B would be on the square between them on the same file, same level. The superior side's R (the mating piece) would be on the same corner square as the lone king, except one level below it. The R would be protected by the B. Thus, aside from the superior side's K guarding 4 critical squares, the B guards 2 critical squares (including one on the upper level), and the R guards 2 critical squares (including one on the level below the Ks). That's if I've visualized this all correctly.

H.G. wrote:

"I don't think KRK is won on a board without corners. The bare King can just flee away from the stong King along the ring. There is no way a Rook can slow it down, if there are only four Rings: you keep attacking the Rook until it leaves the radius where you wanted to go."

I now believe you are correct, H.G. Somehow one night I had imagined a zugzwang could always be arranged even if the superior K was more than 1 file away from a cut off (by the R, to a single rank) lone K, but I was clearly up too late, and since then I neglected to check my conclusion.

This looks like a fabulous game that would seldom be dull. I don't know if one side can force a win or even a significant advantage straight from the opening, but as long as this is a mystery it adds to the charm of the variant. The 2 games between the author and Joe Joyce, circa 2011, were illuminating for me. These were played using the non-rule enforcing preset "4-Handed Chaturanga" that is still currently used to handle any 4 army (though 2 player) Chaturanga variant on Game Courier, it seems.

My tentative estimates for the piece values of this variant would be: S=0.625; P=1; N=3.5; R=5.5 and the fighting value of K=4 (though naturally it cannot be traded). Bear in mind that years ago ZoG estimated the value of an alfil [an S in this variant] on an 8x8 board to be about 1.16, or almost twice what I have it as. I reached that value by taking an initial value for S of (N-1)/8 - for being thrice binded - and then multiplying that by 2 (as a bonus for usually being a speedier short-range leaper than the otherwise somewhat similar N) to get my final value for S.

[edit: some implications of the rules of this particular variant are not totally obvious to me, though I believe I understand them: Firstly, I asked myself, can a player ever capture one of his own pieces (aside from under the special case of the meeting of the 4 ships rule)? That is, can a piece that belongs to his army of the other colour be captured by a piece of the colour that he is moving, e.g. can, say, a yellow king ever capture a red pawn? The answer seems to be clearly 'no'. For in the rules there is stated: "The black armies pieces and pawns can be captured by the yellow and red pieces". Nothing is mentioned about green being able to capture black's pawns and pieces. That said, a similar question I had about the rules was whether, say, a yellow piece can ever be giving check to the player's other (red) king, and the answer again seems to be clearly 'no' (just as a yellow piece or pawn cannot capture a red one). Lastly, perhaps the most vexing question I had was if, say, the red & yellow kings could ever legally be on adjacent squares. In the rules there is stated: "A king also cannot move to a square that is being attacked by an enemy piece, even if that enemy piece's king is in checkmate". There is nothing stated about a king moving to a square attacked by a friendly king (the quoted statement also in a similar way reinforces my conclusion in the previous paragraph). Thus it seems clear that indeed the red & yellow kings could legally be on adjacent squares.]

Back rank or smothered checkmates, along with the large number of playable openings from the start position, and a nice average of 40 moves to a game, are some of the more pleasing peculiarities of standard chess that make it harder for other activities or board games of skill to compete.

I tend to agree most with Dutch World Chess Champion Max Euwe's relative piece values for the pieces, i.e.: P=1; N=3.5; B=3.5; R=5.5; Q=10, noting that some authorites give K=4 for its fighting value (though naturally it cannot be traded), and also noting Horowitz (and others) rate a bishop as being microscopically better than a knight on average, and in both cases I tend to agree, too, so perhaps correct N to =3.49.

Here's a CV allowing the play of 4 chess games at once, winning first game takes war:

https://www.chessvariants.com/play/3d-chess-war

Alice Chess is a 3D chess variant that works very well, with only minor trickery required (i.e. that no piece is allowed to occupy the corresponding square on the opposite board). Not only that, but interesting exchanges of differing piece types can still be made, with there still being a variety of 'major' and 'minor' pieces.

Beautiful.

I've been playing around with the idea of inventing a viable 4D version of Alice Chess, if it's possible, and I thought I'd put a diagram here to study at my leisure. With Directed Alice Chess III by Joe Joyce (an Alice Chess variant played using just 3 boards), for example, a way to make a 4D Alice Chess variant may have already been invented in disguise. That's since a bishop may be able to make a single square diagonal step move (forward or backward) when going onto each of 3 different 2D boards in single steps, as done on 3 consecutive turns, with the bishop possibly finishing on its starting board, but also possibly just one diagonal step from its original square on that starting board. This is not possible in a typical 3D chess variant (e.g. 5x5x5 Raumschach) with, say, a bishop that moves in standard 3D chess fashion, as the bishop could not even return to its starting board if visiting three of the 2D boards in single steps in 3 consecutive turns. However, it could be possible in a 4D variant (i.e. having 4 or more boards, normally, although at least one of the corner 2D boards might be voluntarily excluded), with a 'standard' 4D bishop still changing just 2 (of now 4) co-ordinates. It might also seem to be possible if using 3 somehow otherwise interconnected 2D boards than in typical 3D chess (as could be the case for Directed Alice Chess III), except that then I do not see how a typical bishop (changing 2 co-ordinates as it moves) could possibly finish on its starting 2D board being just one diagonal step away from the square it started on, after visiting 3 different boards in 3 consecutive moves (in the single step fashion I described above) without the interconnection being in effect 4 dimensional. Perhaps a math wizard might try to explain it to a layman like me, if my conclusion is wrong. Meantime, here's a link to Directed Alice Chess III, followed by my test diagram for a possible 4D Alice Chess variant idea: http://www.chessvariants.com/index/msdisplay.php?itemid=MLdirectedalicei

[edit: my original idea to use four 2D boards for a 4D Alice Chess variant idea was to have it like Alice Chess as much as possible, but to allow up to 3 pieces of any colour to occupy any of a set of 4 corresponding squares (e.g. one set would be those with file & rank = a1). That's also with just the two kings additionally being allowed to take an enemy piece occupying any of the corresponding squares that they may move to on the way in finishing their move (thus a double capture move would be possible for a K), but then the only forcible 'basic' mate would seem to be K & Q vs. lone K, which is not totally satisfying for me.]