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Team-Mate Chess. Variant with 8 different pieces, none of which is able to checkmate a bare king on its own. (8x8, Cells: 64) [All Comments] [Add Comment or Rating]
🔔Notification on Thu, Mar 21 09:13 AM UTC:

The author, H. G. Muller, has updated this page.

💡📝H. G. Muller wrote on Tue, May 16, 2023 06:15 AM UTC:

With the fFbWbD there still would be a problem that a pawn in KPK can be more easily caught by the bare King, in a promotion race. Even if on promotion the piece on the promotion square would protect the bonus piece behind it, the bare King could still step forward to attack the piece on the promotion square. (And I don't want that to be protected by the bonus piece.) Which then would have to flee, and give up the protection of the bonus piece.

When a pawn could promote to a pair of 'inverted silver' (FbW) we would not have this problem, as the constellation after promotion is then unapproachable for an enemy king. So the results of a KPK ending would be exactly as in orthodox chess. The silver is a bit strong, though. But it can be made less valuable by allowing it only to capture royals (mkFbmkW). That would not alter its properties against a bare King, but would make it pretty useless in more complex end-games. So that 'unsupported promotion' where only the bonus piece survives is not really an attractive proposition.

Aurelian Florea wrote on Tue, May 16, 2023 04:53 AM UTC in reply to H. G. Muller from Mon May 15 03:48 PM:

This seems elegant to me!

💡📝H. G. Muller wrote on Mon, May 15, 2023 03:48 PM UTC in reply to Aurelian Florea from 02:00 PM:

Well, I don't want the player to always choose the strongest piece plus a bonus. By only offering a piece that otherwise would never be chosen as part of a pair, it can be made a necessary choice. FD already seems very strong for a bonus piece. If that option was available for any Pawn promotion, it might pay to do 'suicide promotions', where you promote unprotected in the certainty that you can keep one of the pair. If the bonus piece was of Pawn value, you would gain nothing that way. This brings me back to fFbW.

[Edit] The fFbWbD might be a good choice for a bonus piece. Because it attacks orthogonally adjacent squares it can in principle deliver checkmate, but with only 4 move targets it is way too weak to do that on its own. It can do it together with all other Team-Mate peaces, though, even the very weak Mortar. In a reasonable number of moves. And it is not color bound. It can even force checkmate together with its mirror image fWfDbF.

So I guess a good solution would be to offer promotion to this mirror-image pair, in the orientation that they do not protect each other. (Which would be a different orientation after a capture than after a non-capture. The pair then should not be worth more than the other pieces, as the value of these pieces should be similar to that of a Ferz (1.5 Pawn). The KPK end-game could still be won through such a promotion. And piece + pawn vs piece could be won if you manage to get the pawn to the (protected) promotion square, as the defending piece then could sacrifice itself for at most one member of the pair.

Aurelian Florea wrote on Mon, May 15, 2023 02:00 PM UTC in reply to H. G. Muller from 09:30 AM:

I was thinking about the FDmsW to be a nice candidate. You don't really feature orthogonal attacks, the piece is not color bound, not too strong , not too weak. I have also considered the weird AH, which is not color bound but which moves around quite akward.

Also why force one bonus piece? There could be a choice here too. I think because things could become too complicated. But the player can then choose winning pairs.

💡📝H. G. Muller wrote on Mon, May 15, 2023 09:30 AM UTC in reply to Aurelian Florea from 08:09 AM:

It seems to have merit. Also because it is a great opportunity to force yet another piece type on the player, creating many new teams. But a Ferz is probably not the best 'bonus piece'. It cannot force mate in combination with several of the other pieces. Which is not a problem for winning KPK, where you would simply pick a piece with which it can. But this is a good opportunity to also reduce drawishness in piece + Pawn vs piece end-games, where after promotion the piece on the promotion square would get traded, so that you have to make do with the bonus piece and the piece that you happened to have left.

A 'Y' (fFbW) would have more 'winning teams', but because it is so weak some of the wins are extremely lengthy. And it would still not work together with the Mortar. And I dislike that it is not fully symmetric.

Perhaps a Camel would make a better bonus piece; it has mating potential together with all other piece types. (But since it is color bound of course not with another color-bound on the same shade.) Camel + Mortar take 74 moves, though.

I also dislike that this pair promotion would only apply to the last remaining Pawn of a player. It would probably not be too distupting to allow it on any promotion if there was no free choice in what the other piece would be. So every Pawn would have the same promotion choice, either a single piece from the initial setup on the promotion square, or a pre-determined pair of two quite weak other pieces (together not worth more than what you could get as a single piece), where the only choice is which of the two you will get on the origin and which on the destination.

I would have to think about which pieces these could be. I don't want it to be possible that they would protect each other, together they should be able to force checkmate, and one of them should be able to force checkmate together with most pieces from the initial setup.

Aurelian Florea wrote on Mon, May 15, 2023 08:09 AM UTC in reply to H. G. Muller from Sun May 14 05:42 PM:

I like the pair promotion idea!

💡📝H. G. Muller wrote on Sun, May 14, 2023 05:42 PM UTC in reply to Fergus Duniho from Mon Apr 17 06:09 PM:

One thing that has always bothered me about this variant, is that the King + Pawn vs King end-game is automatically a draw, as none of the pieces you can promote to could force checkmate on its own. Because of that we lose one of the most subtle elementary end-games in chess.

Of course it would be possible to add a special rule that would allow the last pawn to promote to a piece that does have mating potential (e.g. a Rook). But this would be against the spirit of the variant. Therefore the following idea occurred to me: don't have the Pawn promote to a single piece, but to a pair. One piece could appear on the promotion square as usual, but as a bonus a Ferz would appear on the square the Pawn came from.

🕸Fergus Duniho wrote on Mon, Apr 17, 2023 06:09 PM UTC:

I changed the name of pgnu.png to bgnu.png, since it seems to have been a typo, and /home/chessvariants/public_html/play/pbm/sets/auto-xboard.php was expecting bgnu.png, which was missing.

💡📝H. G. Muller wrote on Tue, Apr 14, 2020 08:55 AM UTC:

As off now, I changed the name of the W-then-B piece from the (historically incorrect) Betzan 'Aanca' to 'Acromantula'. In the Harry Potter series Acromantula refers to a species of giant, poisonous, man-eating spiders of high intelligence. As the piece can move along eight rays, so that its move pattern does resemble a spider seen from above, the name seems fitting.

Jeremy Good wrote on Sun, Nov 9, 2014 01:10 PM UTC:
Speaking only for myself, I had no intention of discouraging an alternate system of nomenclature. At this moment, I have no flash of insight into how to begin one, but my remarks were intended to convey that it would make sense to develop an internationally recognized system that is more accurate and sensitive to language differences. Possibly language, traditionally, has effectively divided people as much as it has united them. Like the scientific community at its best, the chess variant community is and should be international in scope, when we act with deliberate purpose and not mere whimsy and comfort (neither of which should be discounted as important motivating forces for lingual and variant activity). 

IN short, I welcome the dialogue, discussion and any contributions to this subject matter any interested parties may have.

I only ask, if we are to continue this dialogue, that perhaps we start a new thread for it rather than under the rubric Team-Mate Chess.

John Ayer wrote on Fri, Oct 24, 2014 07:55 PM UTC:
Well, it doesn't appear that anyone else is interested.

💡📝H. G. Muller wrote on Fri, Oct 24, 2014 07:29 PM UTC:
So it seems we are now in a situation where there is a sort of general concensus that Aanca in English means something different then Aanca in Spanish, and the latter means the same as Griffon in English.

Well, that happens to be exactly the same situation as with Alfil / Bishop. Now are we going to do something about that? If not, why bother about the Aanca, which is at least 100 times less common?

John Ayer wrote on Fri, Oct 24, 2014 05:19 PM UTC:
Murray on page 348 has a chart for the pieces, giving Spanish and English names, that clearly identifies the aanca with the gryphon, moving one step diagonally, then any number orthogonally (away from the point of origin, as Falkener makes clear).  Betza failed to pay attention.  He also departed from his source, and said so, in deciding that no orthogonal move is necessary.

Jeremy Good wrote on Fri, Oct 24, 2014 01:43 PM UTC:
I enjoy the Betzan lexicon but maybe that's only because I'm used to it. Was it really necessary to create mnemonic devices like Waffle Wazir + Alfil for pieces that were known for hundreds of years before (Waffle = Phoenix). Just because we've been promoting the Betzan lexicon for a decent amount of time here doesn't mean that we can't come up with a new one that works better internationally. Also, this can be a little idiosyncratic like naming your child Emily rather than Susan. I have preferred names for bishop-knight compound and the rook-knight compound but there are several that others prefer and I've noticed variant inventors will often rename well known pieces the way Betza did not too long ago. 

Standardization is something that has to catch on in order to work.

Jeremy Good wrote on Fri, Oct 24, 2014 01:37 PM UTC:
Hi John. Actually that's why Betza named the Aanca "Aanca" but when he named it he implied maybe it was a temporary moniker. For me, it works. Here: "For lack of a name, I'll call it the Aanca (13th century Spanish for 'Gryphon')."

💡📝H. G. Muller wrote on Thu, Oct 23, 2014 08:11 AM UTC:
Well, I am not sure that we should attempt it. When I do a Google search on Aanca, all sources referring to a Chess piece use it in the meaning "Wazir, then Bishop". And there are several hits outside this website, over which we would not have any control anyway.

So I am not sure what actually is the 'confusion'. You say that Gryphon is English for 'Aanca'. This seems to imply that 'Aanca' is only used in some other language to indicate the piece the Piececlopedia describes as Griffon (perhaps the original laguage in which Grand Acedrex was described)? Does Murray explicitly use the word 'Aanca' in his book?

That names of Chess pieces differ from languages to language is normal, and because of that it occasionally also happens that the same name specifies a different piece in one language as in another. Even in English the same name can refer to different pieces in different variants. (E.g. in Carrera Chess Champion is RN, Centaur BN, while in Omega Chess Champion is WAD and Centaur usually means KN.)

I suppose we are also not going to solve the 'Alfil confusion', that in English Alfil means the Shatranj Elephant, while in Spanish it means a FIDE Bishop. So why should 'Aanca' be different? I can perfectly live with it that Aanca in English means W, then B while in some other language it might mean F, then R.

John Ayer wrote on Thu, Oct 23, 2014 02:54 AM UTC:
Unfortunately the Piecelopedia does not make clear that the gryphon is the English name of the aanca, and Betza, who describes the gryphon exactly as Murray did, somehow failed to realize that gryphon and aanca were the same thing, and created a new piece with a name that was already taken.  Can we untangle this confusion?

John Ayer wrote on Thu, Oct 23, 2014 12:18 AM UTC:
Splendid idea!

💡📝H. G. Muller wrote on Wed, Oct 22, 2014 06:05 AM UTC:
Indeed, it is unfortunate that there seems to be a controversy about the name of this piece. But on it is defined as Aanca, and no other name is given for it.

If it would be changed on the Betza bent-riders page (and the reference to it in Tri-Punch Chess) and Aanca would be mentioned on the Griffon page as a synonym for Griffon and appear in the Piececlopedia with its own page under another name, I would follow that. (The new name had better start with an 'A', then, because I already distributed Fairy-Max, and changing the piece ID would make previously saved game files unreadable.) It is a bit strange that Betza, who obviously read the same book, as he even refers to the very same page, would use the name for another piece.

We could of course call in Ancaa instead. It is, after all, a 45-degree rotated version of thr Gryphon, so a slight name modification (as with Mao / Moa) seems justified.

John Ayer wrote on Wed, Oct 22, 2014 01:21 AM UTC:
Murray, on page 348, describing Alfonso el Sabio's Grande Acedrex, says that the Aanca (Gryphon) moves one step diagonally, followed by any number orthogonally away from the point of origin.  Gollon, on page 92, follows this.  I did not find it convenient to go to the library to consult Falkener.  If you want to use a piece that moves one step orthogonally, then continues diagonally away from the point of origin, I think it should have a different name.

💡📝H. G. Muller wrote on Tue, Oct 21, 2014 08:24 AM UTC:
I examined the 3-vs-2 end-games now, and the situation really isn't that much different from normal Chess. There are 6 different ways in which you can pick 2 out of the 4 'minors' you start with. In orthodox Chess one of these is BB, one NN, and the other 4 are BN. There are 4 possible ways to select the defending minor, (in Chess 2x B and 2x N), for 24 possible 3-vs-2 end-games with minors. In Chess only 2 of those 24 are won (BB vs N).

In Team-Mate all 24 possibilities are different. As the Mammoth is significantly weaker than the other minors, it is useful to distinguish strong teams (without M) and weak teams (with M). Turns out all teams (except N+M, which does not have mating potential even against a bare King, and thus is the N+N equivalent of orthoChess) beat K+M, and all strong teams beat K+E. The others are general draws. So 8 of the 24 possible 3-vs-2 end-games with minors are won, against only 2 for orthoChess!

Some of those are only 'half won', however. In particular, when both sides have a color-bound piece (and the defender always has E or M, or it couldn't be won to start with), then a win can in general be forced only if these are on the same color. This is understandable, as when they are of different color the opponent will build his fortress on his color, so that your color-bound piece only hits thin air, and it is basically 2-vs-2. Only F+E vs M can still be won when E and M are of different color, no doubt due to the general clumsiness of the M. For E+M to beat M, the latter must be on the color of the E (to attack it without allowing it to trade?).

It is worth noting that the initial setup dictates that two (opposing) E or M will be on different color, while M vs E will be on the same. This spoils many of the wins, and might actually be an argument to switch to a point-symmetric initial setup. (Tabulated numbers are longest distance to forced 'conversion', i.e. mate or winning capture. Italics means that they refer to a color binding different from in the initial position.)


In orthodox Chess Rook vs minor is always draw, so the fact that a single Rook-class piece in Team-Mate has no mating potential does not hurt there. Rook + minor vs minor is a general win in Chess, however. Turns out it is the same in Team-Mate: (U or C) + (F, N, E or M) vs (F, N, E or M) is a general win in any of the 32 possible combinations.


The surprise came from the Adjutant (J), which I considered a Queen replacement due to its quite-high middle-game value of 7. But in the end-game it turns out pretty weak. Its color binding handicaps it against color-bound defenders, for the same reason as with color-bound minors: the opponent withdraws to the other color, and it becomes useless. And a useless strong piece is just as worthless as a useless weaker piece. Only J+E vs M and J+F vs M can be won on both colors (provided J and E are on different colors, of course), again due to the general weakness of M. J+M cannot beat F or N, however, and J+N cannot beat N. None of this is really a problem, though, as the Adjutant can only be obtained through promotion, and you can opt for C or U instead, which always do the job.


In Chess 2R vs R is won. In Team-Mate there are two different Rook-class pieces, Cobra and Unicorn, and the C+U team beats both U and C. The latter takes very long, though (164 moves), and might be draw in practice. Teams with an Adjutant again do not do well: only J+U can beat C, and the other 3 are draw. (Note that anything I state about Cobra here is really for the Gnu, which unlike Cobra cannot be blocked on the N squares for reaching the (3,1) destinations. But blocking isn't expected to play a significant role in this stage of the game, with hardly anything on the board.)

Because of the poor performance of J the C and U become more likely promotion choices, so the homogeneous pairs U+U and C+C become of interest. U+U vs U is draw. (Probably for the same reason as that KBBKB is draw: it is too difficult to attack the defender without giving him the opportunity to trade.)


Note that JJ also does pretty well here, (when on different color!), probably because they have the property they can drive a bare King with checks to an edge mate without help of their King.

💡📝H. G. Muller wrote on Mon, Oct 20, 2014 05:29 PM UTC:
I was indeed afraid the game would be drawish. But when I tested this in self-play with Fairy-Max, to my surprise only 26 out of 100 games ended in a draw. (When I do that with orthodox Chess, it is some 30%, but the statistical noise with only 100 games is ~5%.)

The point is that 3-vs-2 Pawnless end-games are pretty rare. Most games have the opponent clearly beaten at a stage when both sides still have one or more Pawns, and these then promote unhindered. That unfortunately means real 3-vs-1 end-games are also not that common, but of course much more common than KBNK in orthoChess, as they can happen in so many combinations.

I will certainly investigate the 3-vs-2 matter with tablebases. All pieces are fully symmetric, and the board is 8x8, so I can use the 'fairygen' EGT generator for it, which can do 5-men EGT. Only problem is that it cannot do bent sliders like the Aanca, and I would have to treat the Cobra as a plain Gnu (which in end-games usually makes no difference). My guess is that the 4 minor replacements would all succumb to a minor replacement + something stronger (Rook or Queen replacement), as KBBKN is already won.

Jörg Knappen wrote on Mon, Oct 20, 2014 01:44 PM UTC:Excellent ★★★★★
I like the idea of the many interesting new endgames. I just hope that the endgames 3 vs. 2 are decisive (at least when one of the 3 is an adjutant and the left over piece from the 2 is a minor one); otherwise the game will be very drawish.

💡📝H. G. Muller wrote on Mon, Oct 20, 2014 08:04 AM UTC:
The move you discribe is listed in the Piececlopedia here as that of the Griffon, not Aanca ( ). I tried to look for Aanca on, but I could not find it in the alphabetical index. My information about it comes from Ralph Betza's article on bent riders ( ) to which the Griffon page refers.

If you found contadictory information on this site, please give the link. You also speak about books. Which books?

Not that it means much to me how the piece would be called; I just tried to stick to the consensus as I knew it. I am sure I use other names (like Unicorn) which where already used before in other contexts for a different piece. But WinBoard only offers a limited set of piece images, and I wanted to have a Knight-like symbol for this augmented Knight, and it seemed silly to call a thing that so clearly is depicted as a Unicorn anything else than 'Unicorn'.

The name Phoenix for the WA was taken from Chu Shogi, the name Mammoth was my own invention, since the piece seemed a more 'bulky' version of the Elephant. The name Cobra was also my own invention, inspired by the fact the WinBoard did have an image for it, and that its move pattern in each of the 4 major directions resembles the fangs of a Cobra. (It can also be seen as an extended Knight, but I did not want too many Knight-like symbols, especially not for a piece that already starts next to an orthodox Knight.) The Adjutant was one of Mats Winther's pieces, IIRC.

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