Ratings & Comments

I've never had a problem with them and it's still unclear to me what that would look like.

@Aurelian: I found the Joker difficult to play on-line because you need to have in mind what was the last piece moved and that the Joker mimics. If you play several games in parallel and that a succesive move may happen in the next days, it is difficult. Maybe this is why this interesting piece lacks of popularity. It is probably different when played over a board and in a short time frame.

It seems people are not that interested in this topic. I'm thinking that this is because there is not a lot of experience in games with jokers.

Anyway after a intensive series of games played against the ID these days, I have concluded that on a 10x10 board at least things are ok. What bad thing that can happed is to lose connected pawns, because then the joker is not easily trapped by just moving a pawn. So one has to protect connected pawns, especially near the king, even from sacrifices. That is actually a strategic choice on part of the attacker. I think this is actually a good thing.

So my own verdict is that on a 10x10 board the joker works.

Is it a matter of skill or a matter or perceived randomness?

I would ask that same question about nightriders, but they seem popular anyway. If I'm understanding you, the problem with Jokers is that they're too easy to exchange favorably because they're much stronger at the start than the end. I would expect that to be less of a problem with a very large game, since both players would have more opportunities to use their jokers.

If you're using it in a different armies game, the most important thing would be to have a joker in every army. Do you have an interactive diagram to show an example of a game where this piece might not work?

I have read Eric Silverman's thoughts on powerful pieces now. Trouble with the joker is that it's value is very volatile. In the beginning it is very powerful though. One could argue that maneuvering him it is a matter of skill. This, actually is my conundrum: Is it a matter of skill or a matter or perceived randomness?

By larger boards I mean strictly larger than 8x8. Even in 10x10(where I have 13 piece types) handling the enemy joker is quite tricky. 12x12 could work, too. But larger boards would make games impossible to play if the joker is present. Just imagine Tenjiku shogi with one or God forbid more jokers.

As I have said in my previous comment I have a large palette of piece types represented. This makes things even more complicated.

It could also be that I worry too much, but who knows.

Have you read Eric Silverman's thoughts on poweful pieces? He suggests that it's good to have a few super pieces that dominate the game.

When you say "larger boards" it's not clear if you're talking about the later mentioned 10x10 CWDA or something else. 10x10 doesn't seem large, and you did use the Joker on 10x10 and 12x12 already. If you are talking about something truly larger than 12x12, the obvious way is to have the Joker start at the back and make sure the average piece strength isn't too high.

If you're worried about the Joker dominating the game by being too powerful, don't forget that if it's really that strong the players would be reluctant to trade it away. In that way, strong pieces can be self-balancing.

I could imagine it possibly being a problem if the Joker loses strength quickly so that there's a large advantage in deploying one's Joker first, which would naturally favor the first to move. If that is a problem, a way to counter it would be to carefully choose the moves of the other pieces. Perhaps have more sliding or other blockable moves instead of leaping moves, to allow for pawns to reveal attacks on the Joker by weaker pieces that could be exchanged for it. Another way is to make sure that pieces have simple moves so that a player would be likely to have good options that limit the Joker.

Forget about running the games on ChessV even without the Joker. ChessV does not do riders bent after the second step either. It seems y it is not supported.

This Thread is about games that contain the joker(imitator, jester, fool) piece. The joker piece is here a piece that does not have a move of it's own but borrows the last move of the opponent. It has no other abilities (unlike the one in omega chess), not even double pawn move, en passant or promotion, ability to castle etc. .

The main problem I am facing is that with increased number of piece types (which comes naturally on larger boards) it becomes increasingly powerful. I fear it becomes game breaking. I'm stuck in designing my new games as this piece is also difficult to program (more on this later). Each of the games I am designing has a heavy cavalry piece pair and a light cavalry piece (leapers- their exact abilities are not important now), a bishop pair, a rook pair, a war wagon (as I have renamed the well known falcon), a bent rider, a leaper+slider compound, a queen and of course the royal king. What I have observed by playing against the interactive diagram is that after some pawns and minors are exchanged the joker finds rather easily a central or near central position where it seems almighty. True that the opponent has a joker, too, but it is quite often when one joker paralyzes more pieces than the other. So to me it seems that the joker inserts in the game more a random thing than a good strategy reward. I have to mention that in orthodox chess I have a 1500 rating after the recent increase. Probably stronger players will feel differently. I though of having instead of one all imitating joker to have one that has it's power updated when the enemy moves a light piece and one that has it's power updated when the opponent moves a heavy piece. But this makes a game that already has a steep learning curve into something with an even greater learning curve. I'm writing this in hope for new opinions about including joker in increasingly large games.

On the programming side of things, games that have jokers are more difficult to program. And not because it's move power is difficult to program. I was able to go myself as far, but not further. It is a piece extremely difficult to evaluate. It has been proposed here to aproximate the piece value with the average strength of the enemy pieces. But this does not do it justice. The number of enemy piece types should play a role especially in games where there are many types of piece types like in those I'm designing as mentioned above (riders, leapers, pathers, leapers+riders, bent riders etc.). Moreover chessV does not accept a joker imitating a war wagon (falcon). Some I'm stock only with the interactive diagram which is a poorer AI. I know HG works on something cooler in C++ if I'm not mistaking but this could take many months maybe years.

More I'm thinking of a 10x10 CWDA with jokers. But imitating an opponent's move does not seem like CWDA to me. So I'd go for a transferrer that trasfers the move of a fibnif to a waffle for example. All of these are reasons for why I'm contemplating to take out the joker and replace it with a more normal piece.

But I have reserves to doing that also. First as I have said above I am a merely 1500 chess player. What if introducing the joker is brilliant but I just can't see it. What I find random it is actually strategic for a better player. A NNUE program for example. Also the joker is fun and it offers many tactical possibilities.

For now the best course of action seems to me to make simulations with ChessV without a joker, say jokerless varaints of the variant. That to find out the real piece values when the joker is not involved. An then when HG's more sofisticated program becomes available, try to look at games with joker (never jokers, as many jokers also make each joker more powerful) and see if having a joker makes the games more strategic and tactical, or it makes the game feel more random.

I don't know why the images were like that, but I've redone it to use pngs instead of the svgs directly.

I'd like to make it work with alfaerie if you can suggest what images to use for the gold and silver pieces.

@Daniel Z: The icons displayed on this page are of heterogeneous sizes.

Second point, would it possible to play with Alfaerie graphics? I don't like to use other graphics because it adds another difficulty which is not needed in my opinion.

Well, I knew the fellow might easily be wrong about Komodo. However, previously I had seen Stockfish used a neural network (at least to some extent) starting 2020 - unless that's more false stuff on the internet too (maybe a crusade for truth online could extend beyond chess variants, back to chess itself!?):

https://en.wikipedia.org/wiki/Stockfish_(chess)#:~:text=Starting%20with%20Stockfish%2012%20(2020,leaving%20just%20the%20neural%20network.

edit: it is a similar story as of 2020 for Komodo, apparently:

https://en.wikipedia.org/wiki/Komodo_(chess)#:~:text=On%20November%209%2C%202020%2C%20Komodo,networks%20in%20its%20evaluation%20function.

'In chess analysis, computer tools like Stockfish, Komodo, and AlphaZero help us know the importance of each chess piece during the game. They use calculations to assign a value to each piece based on factors like mobility, king safety, and board position...'(12 Sep 2023, Tato Shervashidze, Chess Coach...)

It is not only false, but it sounds like total nonsense to me. For one, AlphaZero is not comparable in any respect to Komodo or Stockfish; everything is different, and naming them in one breath already exposes the one who says this as completely ignorant on the subject of computer chess. (Which of course doesn't exclude he is a good Chess coach or has a high rating.)

In the past few years there has been a revolution in chess programming, after it had been converging to a method thought to be optimal for several decades. Initially programs were scoring positions at the leaves of a look-ahead search tree by a static (= not playing out any moves) heuristic that is now called a Hand-Crafted Evaluation. Piece values were a major part of that, often interpolated between 'opening' and 'end-game' values depending on the strength of the material still on board. The positional terms were Piece-Square Tables (accounting for mild general position dependence of piece values, without taking note of the location of other pieces, such as that Knights are poor at edges, and even poorer in corners), mobility (the actual number of moves a piece has in the current position), King safety (the number of squares around the King attacked by opponent pieces, and the value and number of these pieces), Pawn structure (passer advance, isolated / backward and doubled Pawns)

These parameters were never calculated (for orthodox Chess engines), but often were tuned. This was done by taking a large data set (like 500,000) of quiet positions from games with known result, and then tweeking all the bonuses and penalties (including piece values) that were used in the HCE until the calcuated evaluation score correlated best with the game result.

Than came AlphaZero out of nowhere, with everything completely different. It used a neural network for evaluation of positions as well as for guiding the search. This network simulates a brain with millions of cells, in some 40 layers, with tens of millions of connections between them. And they tuned the strength of those connections by having the thing play chess against itself. No one knows what each connection represents, but the result is that it eventually it could very accurately predict the winning probability for a position, apparently paying attention even to subtle strategic condiderations.

After that a hybrid form was invented: NNUE (for Easily Updatable Neural Network; no idea why they spelled it backwards...). This uses a conventional (unguided by any NN) search to calculate ahead, but at the end of each line evaluates by a NN of a peculiar design. It does not use explicit piece values, but calculates something very similar to Piece-Square Tables (which can be seen as a sort of piece values specified by location of the piece, and can simulate a plain piece value by specifying that same value on every square). Except that it does have such a PST for each location of the King. So the value of a piece cannot be dependent only on its absolute location, but also on how it is positioned relative to the King. (Well, this was invented for Shogi, and there proximity to the King is often more important than the intinsic strength of the piece type...). And it doesn't have one such a 64x64 table for each piece type, but 256 of them. And all these 256 values of each piece (on its current location, for the current King location) are than fed into a NN of 5 layers with 32 cells per layer, to combine them, until finally a single number appears at the output. This NN is then trained by tuning all the 256x64x64x6 values in the KPST, and the strength of the 4000 connections in the NN to reproduce the win probability of a huge data set of quiet positions, as good as it can.

This works, but after this no one knows what exactly the NN does. None of the values in the KPST in the optimally trained NN have the slightest resemblance to piece values as we know them. We cannot identify a King-Safety part, or a Pawn-Structure part, or a mobility part. It is just one totally integrated complete mess of totally meaningless multiplier parameters, that magically manage to conspire to give a very accurate prediction for who has the better winning chances in a given position. Stockfish and other strong engines now all use NNUE evaluation, (because they typically gain ~80 Elo compared to their original HCE), and the main development towards higher Elo comes from finding better sets for training it, or playing a little bit with the size of the NN. (Large NN can predict more accurately, but slow doen the engine, so that it cannot look as far ahead.)

Not to say I don't trust your post I'm replying to, H.G., but as they say, 'trust but verify'...

A not-too-old answer I saw when I Googled 'Does Stockfish use piece values', as found on 'Quora':

'In chess analysis, computer tools like Stockfish, Komodo, and AlphaZero help us know the importance of each chess piece during the game. They use calculations to assign a value to each piece based on factors like mobility, king safety, and board position...'(12 Sep 2023, Tato Shervashidze, Chess Coach...)

If that's true, such computers are actively doing 'calculating' of their piece values (rather than relying on e.g. statistical-studies-generated ones that are generalizations), on a position-by-position basis in a given game that they are playing.

That's also rather than by using piece values calculated before the start of any play whatsoever, say in the sort of way Betza tried to calculate fairy piece values (or my own cruder way(s) of estimating such values, i.e. in quick and dirty fashion).

Just off topic idea: what if Shogi Pawn will have a value of 1?

The problem with Pawns is that they are severely area bound, so that not all Pawns are equivalent, and some of these 'sub-types' cooperate better than others. Bishops in principle suffer from this too, but one seldomly has those on equal shades. (But still: good Bishop and bad Bishop.) So you cannot speak of THE Pawn value; depending on the Pawn constellation it might vary from 0.5 (doubled Rook Pawn), to 2.5 (7th-rank passer).

Kaufman already remarked that a Bishop appears to be better than a Knight when pitted against a Rook, which means it must have been weaker in some other piece combinations to arrive at an equal overall average. But I think common lore has it that Knights are particularly bad if you have Pawns on both wings, or in general, Pawns that are spread out. By requiring that the extra Pawns are connected passers you would more or less ensure that: there must be other Pawns, because in a pure KRKNPP end-game the Rook has no winning chances at all.

Rules involving a Bishop, like Q=R+B+P are always problematic, because it depends on the presence of the other Bishop to complete the pair. And also here the leveling effect starts to kick in, although to a lesser extent than with Q vs 3 minors. But add two Chancellors and Archbishops, and Q < R+B. (So really Q+C+A < C+A+R+B).

Grandmaster Nigel Short once told me, in so many words, that B+(2 connected passed pawns) generally beats R in an endgame. However, more generally, I have trouble believing N+2 pawns is even = to R, at least in endgames where the pawns are not all part of big healthy pawn island(s), which may be the average case in absolute reality.

The equation Q=R+B+P might seldom exactly hold true in a given chess position. As an observation we discussed long ago, sometimes a mixed bag of units that sticks [defensively] together well holds it own (at the least) vs. a Q, especially if she does not have the initiative (if either side does). However, my intuition tells me that Q is preferable to R+B+P in most cases that could ever arise, i.e. on average (maybe even more so than 2 minors outweigh R+P before an endgame on average), since games tend to open up, and that may favour the Q, for one thing (games often eventually opening up is sometimes given as a reason for thinking B>N on average).

So, a feather in Kaufman's cap here for finding the odd-looking value of the Q compared to R+B+P value. The only issue I have is, Q=R+B+P is such a darn useful/appealing rule of thumb for estimating the value of a Q in quick and dirty fashion, even in chess variants - such a fashion can serve players on CVP's GC while more accurate values are waiting to be found for the ever expanding number of variants played here.

Well, the values that Kaufman found were B=N=3.25, R=5 and Q=9.75. So also there 2 minor > R+P (6.5 vs 6), minor > 3P (3.25 vs 3), 2R > Q (10 vs 9.75). Only 3 minor = Q. Except of course that this ignores the B-pair bonus; 3 minors is bound to involve at least one Bishop, and if that broke the pair... So in almost all cases 3 minors > Q.

You can also see the onset of the leveling effect in the Q-vs-3 case: it is not only bad in the presence of extra Bishops (making sure the Q is opposed by a pair), but also in the presence of extra Rooks. These Rooks would suffer much more from the presence of three opponent minors than they suffer from the presence of an opponent Queen. (But this of course transcends the simple theory of piece values.) So the conclusion would be that he only case where you have equality is Q vs NNB plus Pawns. This could very well be correct without being in contradiction with the claim that 2 minors are in general stronger.

BTW, in his article Kaufman already is skeptical about the Q value he found, and said that he personally would prefer a value 9.50.

If you don't recognize teh B-pair as a separate term, then it is of course no miracle that you find the Bishop on average to be stronger. Because i a large part of the cases it will be part of a pair.

Chess piece values in beginner books (N=B=3, R=5, Q=9) are in fact little white lies to merely simplify their lives (other, unrelated, common white lies also exist - some are the fault of books simply being very old, and/or by poor authors). As you get more experienced/read advanced books, you are told/discover to generally not trade 2 minor pieces for R and P, at least not before the endgame. Similarly, you are told/discover to generally not trade 3 minor pieces for a Q. Also, don't trade a minor piece for 3 pawns too early in a game, as a rule of thumb.

World Champion Euwe, for example, had a set of piece values that tried to take all that into account, yet stay fairly true to the crude but simple to recall beginner values. His values were N=B=3.5, R=5.5 and Q=10 (noting that one thing beginner values get right is 2R=Q+P). Some of the problems of assigning piece values go away if you worry more about satisfying the advanced equations for 2 for 1 and 3 for 1 trades when thinking about such possibilities during a game (or as part of an algorithm).

Euwe did not bother to give a B any different value than N numerically, although he examined single B vs. single N cases in chapter(s) in a Middlegame Book volume (with co-author Kramer). Various grandmasters have historically given a B as having a [tiny] edge in value over a knight - some didn't pin themselves down, and wrote something like N=3, B=3+, the '+' presumably being a small fraction. Since I prefer Q=B+R+P=10, I have B=3.5 to keep that equation tidy, and have N=3.49 completely arbitrarily in my own mind (but generally leave it as 3.5 when writing a set of values, for the sake of simplicity).

To my mind, anyway, there may be a way I haven't mentioned until now to establish close to an absolute true value difference between B and N, if any, if enough decisive 2700+ games can ever be included in a database. For the wins and losses comparison, if you can somehow establish that having the B or the N was The decisive reason for the game's result, after an initial small error or two by the loser, that's the kind of decisive game that really matters. Yes, that raises the number of games you would need in such a database even way more. That's a theory, though again something impractical at present.

"Well-defined value" was used there in the sence of "universally valid for everyone that uses them". (Which does not exclude that there are people that do not use them at all, because they have better means for judging positions. Stockfish no longer uses piece values... It evaluates positions entirely through means of a trained neural net.)  If that would be the case, it would not be of any special interest to specifically investigate their value for high-rated players; any reasonable player would do. I already said it was not clear to me what exactly you wanted to say there, but I perceive this interest in high ratings as somewhat inconsistent. Either it would be the same as always, and thus not specially interesting, or the piece values would not be universal but dependent on rating, and the whole issue of piece values would not be very relevant. It seems there is no gain either way, so why bother?

I may be wrong, but I thought your first two paragraphs in this post of yours I'm replying to indicated that you thought pieces have a 'well-defined value'. Call me mistaken for thinking you meant that there is an absolute truth.