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Comments by H. G. Muller

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This item is a game information page
It belongs to categories: Orthodox chess, 
It was last modified on: 1997-01-10
 Author: Hans L. Bodlaender. Inventor: Joseph  Boyer. Grasshopper Chess. Each player has eight additional grasshoppers.[All Comments] [Add Comment or Rating]
H. G. Muller wrote on 2020-02-19 UTC

You do realize that this drives up the bandwidth it requires to download the page, and increases the server load? Browsers would display a table of individual piece images without any further server access, once the complete Alfaerie set is in their browser cache. And the most commonly used pieces certainly would be, from visiting other pages on this site. Perhaps a rare piece (such as the Grasshopper) would have to requested once (from Cloudfare!), and then the user would have that cached too.

A monolythic image of the entire position would be unique for every article though, and have to be downladed. Using a PHP script to generate the image 'on the fly' means it cannot even be cached by Cloudfare.


UPDATED! This item is a computer program
It belongs to categories: Orthodox chess, 
It was last modified on: 2020-01-23
 Author: Greg  Strong. ChessVUPDATED! This item is a computer program
It belongs to categories: Orthodox chess, 
It was last modified on: 2020-01-23
 Author: Greg  Strong.. (Updated!) Missing description[All Comments] [Add Comment or Rating]
H. G. Muller wrote on 2020-02-16 UTC

Well, while you are at it, could you also check out why the engine version prints such strange values for the time in CECP Thinking Output? That must be pretty trivial to fix.


H. G. Muller wrote on 2020-02-16 UTC

I presented the position to ChessV 2.2RC1, and after 5 min (the time it reports itself is bogus!) it produced a move at 32 ply:

dep	score	nodes	time	(not shown:  tbhits	knps	seldep)
32	+169.59 	106.2M	8:50:53	f2f3 f5e5 d4d1 e5e6 f3f4 e6f6 d1e1 f6g6 f4g4 g6f6 g4f3
31	+169.59 	45.1M  	3:35:35	f2e3 f5f6 e3e4 f6g5 d4d3
30	+169.58 	28.1M  	2:11:14	f2e3 f5e5 d4d3 e5f5 e3d4 f5f6 d4e4 f6e6 d3d5
29	+169.55 	19.1M  	1:25:46	f2e3 f5e5 d4d1 e5f5 d1d5 f5f6 e3e4 f6e6 d5d2 e6f6 d2a2 f6e7 e4e5 e7d7 e5d5 d7e7 a2a5 e7f7 a5a3 f7f8 a3a7 f8g8 d5d6 g8f8 a7b7 f8g8
28	+169.55 	15.9M  	1:08:52	f2e3 f5e5 d4d1 e5f5 d1d5 f5f6 e3e4 f6e6 d5d2 e6f6
27	+169.55 	13.3M  	56:28.33	f2e3 f5e5 d4d1 e5f6 e3e4 f6e6 e4f4 e6f6 d1d6 f6e7 f4e5 e7f7 e5e4 f7e7
26	+169.55 	11.1M  	46:51.12	f2e3 f5e5 d4d1 e5f6 e3e4 f6e6 e4f4 e6f6 d1d6 f6e7 f4e5 e7f7 e5e4 f7e7
25	+169.55 	8.86M  	37:24.84	f2e3 f5e5 d4d1 e5f6 e3e4 f6e6 e4f4 e6f6 d1d6 f6e7 f4e5 e7f7 e5e4 f7e7
24	+169.55 	6.49M  	27:22.68	f2e3 f5e5 d4d1 e5f6 e3e4 f6e6 e4f4 e6f6 d1d6 f6e7 f4e5 e7f7 e5e4 f7e7 e4d5 e7f8 d6e6 f8f7 e6e1 f7f8
23	+169.55 	5.23M  	22:09.12	f2e3 f5e5 d4d1 e5f6 e3e4 f6e6 e4f4 e6f7 f4f5 f7e7 d1d2 e7f7 d2d8 f7e7 d8d5 e7f8 f5e5 f8f7
22	+169.55 	3.91M  	16:38.40	f2e3 f5e5 d4d1 e5f6 e3e4 f6e6 e4f4 e6f7 f4f5 f7e7 d1d2 e7f7 d2d8 f7e7 d8d5 e7f8 f5e5 f8f7
21	+169.55 	2.79M  	12:06.96	f2e3 f5e5 d4d1 e5f6 e3e4 f6e6 e4f4 e6f7 f4f5 f7e7 d1d2 e7f7 d2d8 f7e7 d8d5 e7f8
20	+169.55 	2.39M  	10:25.56	f2e3 f5e5 d4d1 e5f6 e3e4 f6e6 e4f4 e6f7 f4f5 f7e7 d1d2 e7f8 d2d8 f8f7 d8d5 f7e7 d5d3 e7f8 d3d6 f8f7 d6e6
19	+57.24 	1.85M  	8:09.84	f2e3 f5e5 d4d1 e5f6 e3e4 f6e6 e4f4 e6f7 f4f5 f7e7 d1d2
18	+169.56 	1.42M  	6:22.20	f2e3
17	+169.56 	1.13M  	5:12.00	f2e3
16	+169.56 	895583	4:14.28	f2e3 f5e5 d4d1 e5f6 e3e4 f6e6 e4f4 e6f7 f4f5 f7e7 d1d2 e7f8 d2d8 f8f7 d8d5 f7e7 d5d3
15	+57.24 	696806	3:22.80	f2e3 f5e5 d4d2 e5f6 e3e4 f6e6 d2d5 e6f7 e4f5 f7e7 d5d3
14	+57.04 	435297	2:11.04	f2f3 f5e5 f3e3 e5f6 e3f4 f6e6 d4d3 e6e7 f4f5 e7f7 d3d7 f7e8 f5e6 e8f8 e6d6
13	+56.96 	285881	1:27.36	f2f3 f5e5 d4d3 e5f6 f3f4 f6e6 d3d4 e6e7 f4e5 e7f7 e5f5 f7e7 d4d5
12	+56.88 	187028	0:57.72	f2e3 f5e5 d4d3 e5f6 e3e4 f6e6 e4f4 e6e7 f4e5 e7f7 d3d7 f7g6 e5f4
11	+56.80 	115957	0:34.32	f2f3 f5e5 f3e3 e5f6 e3e4 f6e6 d4d5 e6e7 e4e5 e7e8 e5e6
10	+56.72 	68603  	0:20.28	f2f3 f5e5 f3e3 e5f6 e3e4 f6e6 e4f4 e6e7 f4e5 e7e8
9	+56.72 	39705  	0:12.48	f2f3 f5e5 f3e3 e5f6 e3e4 f6e6 e4f4 e6e7 f4e5
8	+56.64 	23739  	0:07.80	f2f3 f5e5 f3e3 e5f6 e3e4 f6e6 d4c4 e6d6
7	+56.64 	12952  	0:04.68	f2f3 f5e5 f3e3 e5f6 e3e4 f6e6 d4c4
6	+56.64 	5601    	0:03.12	f2f3 f5e5 f3e3 e5e6 e3e4 e6e7
5	+56.64 	2579    	0:01.56	f2f3 f5e5 f3e3 e5e6 e3e4
4	+56.52 	1034    	0:01.56	f2f3 f5e5 f3e3 e5e6
3	+56.56 	418      	0:01.56	f2f3 f5e5 f3e3
2	+56.52 	121      	0:01.56	f2f3 f5e6
1	+56.64 	28        	0:01.56	f2f3
0	#

So like micro-Max it finds a mate score pretty fast; difference is that it seems to be that the pretty slow over-the-horizon mate it finds first isn't improved as much as the depth goes up. Still it is strange that it wouldn't simply play out the mating line it found, and is now in its TT, in the following moves.

[Edit] Umm, I might misinterpret the 169.xx scores as mate scores: when I let ChessV play out this position against itself there do appear standard mate scores at the end. Strange thing is that after the black engine admits to being 'mated-in-1' is its last move, the white engine crashes without performing the checkmate.


H. G. Muller wrote on 2020-02-16 UTC

It could be that the new condition just makes hash cuts so rare that the damage they do is not apparent. And can you still solve Fine #70 with this new condition?

Some of these end-games are really difficult (like KBNK), but KRK is not amongst those. If the start position is not extremely unfavorable (like the shown mate-in-12 rather than the worst-case mate-in-16), a fresh search should show you a mate score after a few seconds. Once there is a mate score, it should just start playing from the mating line that is now in the TT. Just walking the winning King to the center should already be enough to get better than mate-in-12.

How long does it take ChessV to get a mate score from the given KRK position, and what depth does it reach? Not being able to act out an already found mate would point to entirely different problems than not finding the mate in the first place.


H. G. Muller wrote on 2020-02-15 UTC

This is very strange. Why do you need custom evaluation for KRK in the first place? Fairy-Max had absolutely no trouble to win KRK on its normal evaluation. (Which has Rooks completely neutral, and use the parabolic centralization table for Kings.) In the latest Fairy-Max version I use what you could call custom evaluation for checkmating a bare King (it just multiplies the centralization bonus for that King by a large factor), but that was only needed for end-games with many centralizing pieces (such as KFFFK in Makruk), because these did not bother to leave the center just for driving a single piece into a corner. Checkmating with Rook is very easy on any size board; you almost need no search depth for it at all. You just shephard the King towards the corner with your Rook, keeping the latter protected from behind by your King.

I suppose you do switch off null move?

The only thing I can think of that causes what you describe is contamination of the hash score with draw scores resulting from repetitions. What happens when you disable repetition detection (accepting PV hash cutoffs)? I don't really understand how a line that makes progress could get draw scores from this, though.

Can you post a game of how it typically plays KRK? (Best would of course be one that it bungles.)

Here is thinking output from a version of Fairy-Max that doesn't use the special bare-king evaluation, for position 8/8/8/5k2/3R4/8/5K2/8 w - 0 1 :

mover viewpoint		fewer / Multi-PV margin = 0 / more
exclude: none best +tail                                          
dep	score	nodes	time	(not shown:  tbhits	knps	seldep)
28	  #12 	121.4M	1:17.65	1. Kf3 Ke5 2. Rd3 Kf6 3. Re3 Kg5 4. Re5 Kg6 5. Kg4 Kf6 6. Re4 Kg6 7. Rf4 Kh6 8. Kf5 Kg7 9. Kg5 Kh7 10. Kf6 Kh8 11. Kf7 Kh7 12. Rh4 
27	  #13 	61.4M  	0:40.03	1. Kf3 Ke5 2. Rd3 Kf6 3. Re3 Kg5 4. Re6 Kf5 5. Re4 
26	  #12 	46.8M  	0:30.38	1. Kf3 Ke5 2. Rd3 Kf6 3. Re3 Kf5 4. Re4 
25	  #12 	28.3M  	0:18.23	1. Kf3 Ke5 2. Rd3 Kf6 3. Re3 Kf5 4. Re4 
24	  #12 	15.6M  	0:09.85	1. Kf3 Ke5 2. Rd3 Kf6 3. Re3 Kf5 4. Kg3 
23	  #12 	10.3M  	0:06.45	1. Kf3 Ke5 2. Rd3 Kf6 3. Re3 Kf5 4. Re4 
22	  #13 	7.44M  	0:04.55	1. Kf3 Ke5 2. Rd3 Kf6 3. Re3 Kf5 4. Re2 Kg5 5. Re5 
21	  #14 	5.88M  	0:03.52	1. Kf3 Ke5 2. Rd3 Kf5 3. Re3 Kg5 4. Re5 Kg6 5. Kg4 Kf6 6. Kf4 
20	  #18 	4.72M  	0:02.74	1. Kf3 Ke5 2. Rd1 Ke6 3. Kf4 Kf6 4. Re1 Kg6 5. Re3 Kf6 6. Re5 Kg6 7. Kg4 
20	  #22 	4.50M  	0:02.59	1. Ke2 Ke6 2. Kf3 Kf6 
20	+4.59 	3.68M  	0:02.07	1. Ke3 Ke5 2. Rd8 Kf5 3. Re8 Kg5 4. Ke4 Kf6 5. Re5 Kg6 
19	+4.57 	2.37M  	0:01.27	1. Ke3 Ke5 2. Re4 Kd5 3. Kd3 Kc6 4. Kd4 Kd6 5. Re5 Kc6 6. Rd5 Kc7 7. Kc5 Kb7 8. Rd6 Kc7 9. Kd5 Kc8 10. Ke4 
18	+4.56 	1.54M  	0:00.81	1. Ke3 Ke5 2. Re4 Kf5 3. Kf3 Kg6 4. Rf4 Kg5 5. Kg3 Kh5 6. Rg4 Kh6 7. Rg8 
17	+4.55 	1.12M  	0:00.57	1. Ke3 Ke5 2. Re4 Kf5 3. Kf3 Kg6 4. Rf4 Kg5 5. Kg3 Kg6 6. Kh4 Kg7 7. Kg5 Kh7 8. Rf7 Kg8 9. Kf6 
16	+4.54 	729185	0:00.35	1. Ke3 Ke5 2. Re4 Kf5 3. Kf3 Kg6 4. Rf4 Kg5 5. Kg3 
15	+4.54 	518699	0:00.25	1. Ke3 Ke5 2. Re4 Kf5 3. Kf3 Kg6 4. Rf4 Kg5 5. Kg3 
14	+4.54 	354924	0:00.15	1. Ke3 Ke5 2. Re4 Kd5 3. Kd3 Kd6 4. Kd4 Kc6 5. Re6 Kc7 6. Kd5 Kd7 7. Ke5 
13	+4.53 	218794	0:00.09	1. Ke3 Ke5 2. Re4 Kd5 3. Kd3 Kd6 4. Kd4 Kc6 5. Re6 Kb5 6. Kd5 Kb4 7. Ke5 
12	+4.53 	150300	0:00.06	1. Ke3 Ke5 2. Re4 Kf5 3. Kf3 Kg5 4. Rf4 Kg6 5. Kg4 Kh6 6. Kf5 Kh5 
11	+4.52 	107753	0:00.04	1. Ke3 Ke5 2. Re4 Kf5 3. Kf3 Kg6 4. Kf4 Kf6 5. Re3 Kg6 6. Ke4 
10	+4.50 	54436  	0:00.01	1. Ke3 Ke5 2. Re4 Kf5 3. Kd4 Kf6 4. Re5 Kg6 5. Ke4 Kf6 
9	+4.52 	36093  	0:00.01	1. Ke3 Ke5 2. Re4 Kf5 3. Kd4 Kf6 4. Re5 Kg6 5. Ke4 
8	+4.51 	20251  	0:00.00	1. Ke3 Ke5 2. Re4 Kf5 3. Kd4 Kf6 4. Re5 Kg6 
7	+4.50 	9192    	0:00.00	1. Ke3 Ke5 2. Re4 Kf5 3. Re8 Kf6 4. Ke4 
6	+4.49 	5719    	0:00.00	1. Ke3 Ke5 2. Re4 Kf5 3. Kd4 Kf6 
5	+4.49 	2747    	0:00.00	1. Ke3 Ke5 2. Re4 Kf5 3. Kd4 
4	+4.48 	559      	0:00.00	1. Ke3 Ke5 2. Re4 Kf5 
3	+4.48 	223      	0:00.00	1. Ke3 Ke5 2. Re4 
2	+4.48 	23        	0:00.00	1. Ke3 Ke5 
1	+4.49 	13        	0:00.00	1. Ke3 

Piece Values[Subject Thread] [Add Response]
H. G. Muller wrote on 2020-02-14 UTC

Strange anomaly

I have started an attempt to determine piece values on a 12x12 board, about which very little is known. I use Fairy-Max self-play for this. To not make the games too long, the basic start position I use consists of a FIDE army augmented with 4 Pawns (to close the Pawn rank). So the board is pretty thinly popuated. The 4 central Pawns start on 4th rank, to speed up engagement, but the 3 Pawns in each wing start on 2nd rank, to provide some King shelter. The Knights also start in a somewhat advanced position, on 3rd rank behind the central Pawns, as does the Queen (to not have too many unprotected Pawns in the start position.

To determine piece values I delete some pieces from this setup, or sometimes replace them by fairy pieces. The side with the weaker piece can be compensated by giving the opponent Pawn odds, for which I always delete the same Pawn (on the h-file). Such Pawn odds alone results in a 68-70% win of the side with the extra Pawn. I only trust results when the total advantage is closer to equality than Pawn odds.

I don't want to delete more than a single Pawn, because Pawns are highly cooperative pieces, and I cannot be sure that deleting two Pawns gives twice the advantage of deleting a single one. By always granting the same simple Pawn advantage (or none at all), I can get a reliable 'measuring stick' on which the values of other pieces can be mapped. This poses a problem if there is a gap of more than 2 Pawns in the 'piece-value spectrum', though: I cannot play those 1-on-1 without getting an imbalance that is too extreme. I solve that by also introducing fairy pieces with values in the gap, and also determine their value.

I try to avoid Bishops, (and color-bound pieces in general) because of the pair-bonus problem, which would introduce yet another unknown. Which, if not handled properly by the engine, might invalidate the results. So I tried to find a very 'Bishop-like' piece that is not color bound. My first choice was this: to break the color binding of a Bishop, I gave it Wazir moves. To compensate for that (and prevent mating potential), I take away the Ferz moves. But to not affect the more distant B moves, they can still be blocked on the F squares. (So basically this is a Tamerlane 'Picket' + Wazir.)

Such a modified Bishops beats a Knight on 12x12 (as ordinary Bishops also do). The strange thing is that when I then handicap them with Pawn odds, they still beat the Knight, by about the same score. The extra Pawn doesn't seem to help the Knight at all! I have never seen that before; normally deleting a Pawn lowers the score by about as much as the pure Pawn-odds advantage. I watched a few games, and often they end in Knight + Pawns vs modified Bishop + Pawns, where the Knights are still judged by the engine to be ahead (because there are more Pawns on their side). But the Knight then almost always loses. The 'WazirPicket' can easily prevent advance of many isolated Pawns, by guarding a diagonal. And by just stepping in front of a Pawn it attacks as well as blocks it, so that the Pawn easily falls. Even connected passers are easily destroyed this way, if they still have far to go. (And on 12x12 they usually have; I use promotion on last rank only.)

I guess the WazirPicket is just unrepresentatively dangerous to Pawns, in the absence of pieces that can protect those. (And Knights are pitifully slow on 12x12...) So that the value of opposing Pawns shrinks to almost nothing in the late end-game.

My next attempt at a non-color-bound substitute for a Bishop will only change the mF moves of a Bishop to mW, but leaves the captures in place. This will also have the advantage that it cannot be blocked on a square that it doesn't attack, so that it cannot be blocked with impunity (as lame leapers can). Such a piece cannot do more damage to Pawns than ordinary Bishops can, but the mW move does allow it to switch color on non-captures. (Hence I dubbed it Swishop.)

 


Caching[All Comments] [Add Comment or Rating]
H. G. Muller wrote on 2020-02-13 UTC

Well, if there are no other contenders for that rule, then it would certainly help me. Or perhaps exempt .js files in general: browsers would typically cache those themselves, so they won't request them even from Cloudfare unless the user would explicitly bypass or flush his browser cache.

But why are you so certain that you cannot control Cloudfare through a script on chessvariants.com? I guess you flush files from the Cloudfare cache (or perhaps the entire cache) through a TCP/IP connection. So why not have the submission script open a TCP/IP connection to it, and send the required commands over it? Or do you have to solve some "I am not a robot" puzzle there?


H. G. Muller wrote on 2020-02-13 UTC

Such a setup breaks the possibility to change any of the articles and their associated uploaded files, as these are not PHP scripts. It makes you entirely dependent on manual intervention, because any update will with certainty be screened from all remote clients. If you want that, notification of the site admin or an editor that such intervention is needed should be automatic; having to post requests through the comments channel clutters the comments with garbage, as is now happening to this article.

Can the submission / upload script not automatically notify an empowered person that action is required, through e-mail or some specific requesting mechanism? It would of course be even better if these scripts would invoke a program that would purge the cached version in Cloudfare automatically.


This item is a game information page
It belongs to categories: Orthodox chess, 
It was last modified on: 2015-03-19
 Author: H. G.  Muller. Maka Dai Dai Shogi. Pieces promote on capture, some to multi-capturing monsters. (19x19, Cells: 361) [All Comments] [Add Comment or Rating]
H. G. Muller wrote on 2020-02-13 UTC

I discussed this once with an official of the Japanese Chu Shogi Association, who wanted to revive the interest in Maka Dai Dai Shogi, and had written a manuscript defining the 'modern' rules. He insisted that it would be the last piece captured. And for a Lion Dog he insisted that jumping two squares out to capture something, and then retract one square to capture what you jumped over, was not a legal Lion-Dog move, but that you would always have to capture what is on the adjacent square in the outgoing leg if you wanted to finish there.

It didn't make much sense to me. I would also be happy if you were allowed to choose. Of course this is all highly theoretical; no one would allow both his most-valuable pieces to be in Lion or Lion-Dog range.


Caching[All Comments] [Add Comment or Rating]
H. G. Muller wrote on 2020-02-13 UTC

As far as I am concerned, something is broken when doesn't fully work as it should. But this doesn't seem worth quibbling about, as long as we agree there is an issue.

It is unfortunate enough that the list of comments to the Betza Notation article gets cluttered with messages like this not directly related to the topic, and losing all relevance in a short time.

@Ben:

How do you know it is the browser? It doesn't look like it is the browser to me. In FireFox, when I press Shift during reload, it will always bypass the cache for the files the main document links to (like images or JavaScript code). And the main page will never be cached. But that does not happen here: I access chessvariants.com/membergraphics/MSinteractive-diagrams/betza.js directly (so that the browser should never have cached it), and it still shows the old content. When I load the directory it is in, it gives the file with today's download date, so the correct file must be on the server.

When I append the requested betza.js link with a dummy CGI argument "t=19", to be sure no one can cache, I do see the altered content. But if I then omit it again, it reverts to the old content.

This happens on two browsers (FireFox and Chrome). After I use the Chrome menu to delete all cached files, I still get the old contents. I don't think it are the browsers.

I guess adding a dummy CGI argument that contains a dynamically requested time to the link in the page that refers to betza.js should fix it. But it is crazy that such a work-around would be needed.

[Edit] I added the dummy "?t=19" suffix to the link to betza.js in the Betza Sandbox comment, so that this at least uses the updated version. But it is not really a feasible solution to do that in every page that refers to the file. And when I update again the "?t=19" would be the cached version, and all the suffixes would have to be updated to a value never used before...


This item is a reference work
It belongs to categories: Orthodox chess, 
It was last modified on: 2003-01-25
 Author: Glenn  Overby II and Ralph  Betza. Inventor: Ralph  Betza. Betza Notation. A primer on the leading shorthand for describing variant piece moves.[All Comments] [Add Comment or Rating]
H. G. Muller wrote on 2020-02-13 UTC

OK, I can get it too now. It only appears to add the spurious Rook moves in two directions, and only when the mount is on an F square. In fact the piece behaves like a bifurcator, going to the second leg not at the mount, but one step in front of it. It is apparently the yafscpF contribution that does this.

And it seems to be caused by the 'original' use of 'p' in the final leg. When I use 'p' in the new meaning of ending on an occupied square for a non-final leg, as in yafscpafF, everything works fine. Which is surprising, as the Betza parser should convert p to paf on any final leg, on reading the description, so that they really should be the same thing. This is apparently what goes wrong.

This is definitely a bug in the Interactive Diagram code. I will look into it. Thank you for reporting it!

[Edit] OK, I have fixed it. The problem was that the Betza parser turned the old-style 'p' on final legs to a multi leg move, by making it into a non-final leg with 'p' mode, and adding an extra leg for the part of the trajectory after the mount. In the internal representation each leg lists how many legs still follow, so that they can be skipped whenever an earlier leg cannot be completed. The existing parser did not increase this skip count on legs before the leg with the old-style 'p', so that when they were blocked the newly added leg for after the mount was not skipped, but was considered another independent move. So when the first F step in yafscpF could not be made because of a blocker, it would transplant the path that should have come after the mount in the second leg to the piece itself.

I also fixed another problem: finite-range hoppers were not working properly. E.g. pR5 would not be an R5 that had to pass over exactly one obstacle, but would be a pR that could only land on the first 5 squares behind the mount. I think in original Betza notation the range should apply to total range, and changed the code accordingly. Downside is that it is not easily possible now to describe hoppers with a fixed finite range after the hop. (Unless that range is 1, in which case the range-toggling 'g' modifier can be used.) I suppose an 'Extended Grasshopper' that could land (precisely) 2 squares behind its mount can still be described as gafafQ (where gafQ would be an alternative notation for gQ, the normal Grasshopper).

Note that caching on this website is broken, so that you might not be able to benefit from the fixed diagram code I uploaded until the site maintainer takes manual action to make the changes visible!


H. G. Muller wrote on 2020-02-12 UTC

It seems to work for me: I get a 'Pao version' of the Gryphon. Can you give an example of a constellation of pieces where it doesn't work?


H. G. Muller wrote on 2020-02-12 UTC

No, it would not. Betza atoms never describe null moves (unless one would have defined an atom especially for that), and even if the number of steps is variable, such as in B or R, it must at least make one step and cannot stay in place. The use of the 'a' modifier to define multiple legs doesn't alter that: each leg must at least take 1 step (and if it is a leaper leg, that would be the only step). All the moves you specified are bent two-leg moves, (they have 'fs' after the 'a'), and a Rook move isn't.

BTW, I would use gafscF instead of pafscB1; 'g' describes a range-toggle after hop, as in the Grasshopper (slide -> leap) or Contra-Grasshopper (leap -> slide). What you wrote should also work, but is a bit more cryptic. gafscF means an F step to the mount, followed by a Rook slide that can only capture.


This item is a piececlopedia entry
It belongs to categories: Orthodox chess, 
It was last modified on: 2001-04-06
 Author: Hans L. Bodlaender. Inventor: J. de A. Almay. Boyscout. Moves in a diagonal zigzagline. Also known as Boyscout.[All Comments] [Add Comment or Rating]
H. G. Muller wrote on 2020-02-01 UTC

It seems pretty obvious that this piece should be far stronger than an ordinary Bishop. Even the "chiral half" of it (which only has the moves that start with a turn in the same relative direction) has on average more moves than an ordinary Bishop; on non-edge squares it in fact has the same number of moves as a Rook. With both the left-handed and the right-handed moves it doesn't really have double the number of moves, as half of the moves overlap. But even then being able to go there along two paths must be worth something extra beyond having just a single way to get there. (There is no compensation for the fact that the left-handed and right-handed moves overlap on the F-squares, though, as these moves were unblockable anyway.)


This item is a game information page
It belongs to categories: Orthodox chess, 
It was last modified on: 2017-08-07
 Author: H. G.  Muller. Inventor: Jean-Louis  Cazaux. Metamachy. Large game with a variety of regular fairy pieces.[All Comments] [Add Comment or Rating]
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.


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.

 


The birth of two variants: Apothecary chess 1 & Apothecary chess 2[Subject Thread] [Add Response]
H. G. Muller wrote on 2020-01-03 UTC

I though about castling for a while but it does not seem a good thing. It would have involved one step diagonally back which is also uncomfortable. Any thoughts are appreciated.

For this reason I did start the King in Elven Chess on the back rank, and put one of the unorthodox pieces (the Lion) in its place next to the Queen.


This item is a Zillions-of-Games file
It belongs to categories: Orthodox chess, 
It was last modified on: 2001-01-26
 Author: Larry L. Smith. Inventor: Edgar Rice Burroughs. ERB Jetan ZIP file. Implements different possible rules for Jetan.[All Comments] [Add Comment or Rating]
H. G. Muller wrote on 2019-11-27 UTC

Is it better than Nebiyu?


This item is a game information page
It belongs to categories: Orthodox chess, 
It was last modified on: 2013-03-25
 Author: Edward  Jackman and Fergus  Duniho. Inventor: Vernon Rylands Parton. Alice Chess. Classic Variant where pieces switch between two boards whenever they move. (8x8x2, Cells: 128) (Recognized!)[All Comments] [Add Comment or Rating]
H. G. Muller wrote on 2019-11-26 UTC

This is a trial for using the Interactive Diagram for Alice Chess. Custom-supplied functions BadZone and WeirdPromotion take care of refusal of moves to squares of which the mirror square is occupied, and take care of shuttling the moved piece to the other board, respectively. The boards are separated by strip of 'hole' squares, which has to be two files wide to prevent Knights from crossing it.

files=18 promoChoice=NBRQ graphicsDir=../membergraphics/MSelven-chess/ whitePrefix=w blackPrefix=b graphicsType=png squareSize=33 symmetry=none royal=6 pawn::::a2,b2,c2,d2,e2,f2,g2,h2,,a7,b7,c7,d7,e7,f7,g7,h7 knight:N:::b1,g1,,b8,g8 bishop::::c1,f1,,c8,f8 rook::::a1,h1,,a8,h8 queen::::d1,,d8 king::KisO2::e1,,e8 hole::::i1,i2,i3,i4,i5,i6,i7,i8,j1,j2,j3,j4,j5,j6,j7,j8

I implemented e.p. capture as a move by the Pawn on the board where the doubly pushed Pawn started. This seemed the least illogical way to do it, as the e.p. square on that board will always be empty (or the double push would not have been allowed). And it is the square the double push really passed over, and thus where it could have been blocked. The move could still be illegal because the corresponding square on the other board is occupied, but that is normal for any move to an empty square in Alice Chess that would be legal on its own board. There has to be no extra rule to prevent double capture this way. This method of e.p. capture corresponds to one where the doubly pushed Pawn must first make a single retrograde step before being captured, rather than replacing its double step by a single step. That this is not the same is the fault of an Alice double push not really being two consecutive single pushes.

I still have a comment to make about the legality of moves (an aspect that the diagram doesn't address). The ambiguity here seems to be caused by not making proper distinction between legal and pseudo-legal moves, but heaping them all under the term 'legal'. A more precise description would have said that a move in Alice Chess is pseudo-legal if (before transfer) it would have been pseudo-legal in orthodox Chess on the board where it is made, and the target square on the other board is empty. And then an Alice move is legal (as usual) when it does not expose the King to pseudo-legal Alice capture. This prevents solving distant checks by interposing a piece that was on the board where the checked King resides (but then disappearing to the other board, so that the King can be captured) from being considered legal. Despite the fact that they would have been perfectly legal orthodox Chess moves on the board with the King.


This item is a game information page
It belongs to categories: Orthodox chess, 
It was last modified on: 2014-05-02
 By Carlos  Cetina. Symmetric Chess. Missing description (9x8, Cells: 72) [All Comments] [Add Comment or Rating]
H. G. Muller wrote on 2019-11-25 UTC

That is because Nebiyu is an engine, and engines are not supposed to be used directly, but only through mediation of a Graphical User Interface like WinBoard. It is then WinBoard which will take care of launching the engine's .exe file, and send it the proper (text) commands to do something useful.

So the proper procedure is to start WinBoard (either as game viewer without any engine, or for playing against some other engine), then open the Engine -> Load first Engine menu dialog, use the 'browse button' behind the 'Engine' text entry to locate NebiyuAlien.exe, and then 'OK' the dialog. This will make WinBoard start Nebiyu in the background, (possibly terminating the engine that was in use before), and consult it through the appropriate communication whenever it needs it to make or suggest a move. You can then select one of the supported variants from the File -> New Variant dialog.

This procedure will also add NebiyuAlien to WinBoard's 'Engine List', which will be displayed in a listbox on the left in the Load Engine dialogs, so that you can just click on it when you want to use it again in a later session, without having to browse for it first. This Engine List will also be displayed in the comboboxes of WinBoard's Startup Dialog, so that a next time when you start WinBoard you can select Nebiyu immediately, as first or as second engine. (A second engine is only needed when you want to play two engines against each other, through the Mode -> Two Machines menu item.)


H. G. Muller wrote on 2019-11-25 UTC

There are many more links on that page, which come into view when you scroll down. The Nebiyu version I know is at the link Nebiyu 1.45. There seems to be a newer version 1.5, but from the decription of it I am not sure it would be useful untill you train it first, and I never used it myself. IIRC the Nebiyu 1.45 package contains several executables (also covering games other than chess variants), but the one you should run for CVs is NebiyuAlien.exe. The game definitions for that are all in the file alien.ini, which is sort of self-documenting. The file starts with a series of piece definitions, after which a series of game definitions using those pieces follows.


H. G. Muller wrote on 2019-11-25 UTC

For the second, I would be grateful if you, Fergus, HG or anyone else tell me of any program (preferable of chess or chessvariants) that I could download.

There is Fairy-Stockfish, which is very much worth having. But it is not an independent app that goes accompanied with an installer. Just something you unzip in a folder of your choice, after which you have to point WinBoard to the executable through the Load Engine dialog, so that it can use it as an engine.

The same holds for Nebiyu, which is not as strong as Stockfish, but rather easy to configure for playing new chess variants.


This item is an unknown type!
It belongs to categories: Orthodox chess, 
It was last modified on: 2015-04-08
 Author: Fergus  Duniho. Games on Game Courier. A listing of Chess variants for Game Courier, ranked by number of times played.[All Comments] [Add Comment or Rating]
H. G. Muller wrote on 2019-11-24 UTC

@Fergus: I definitely agree that for having sufficient generality it is necessary to be able to resort to some Turing-complete programming language. But a quite large fraction of CVs would not do anything that is not standard (in the sense that hundreds of other CVs would not do exactly the same). If exposing those who want to create presets to the code for such standard tasks discourages them, it would be better not to do that. And it would not be that difficult to achieve that.

One solution could be to reserve the code edits in the preset Edit form only for enforcing / implementing non-standard rules (and perhaps show them only on request, after ticking a checkbox that you want them). And have the code for the very common tasks, such as forbidding capture of own pieces, testing for check / stalemate / checkmate, 50-move draw, repetition draw be added automatically when the user requests this through ticking a checkbox, (e.g. "can expose royal to capture") selecting from a drop-down menu (e.g. "stalemating the opponent wins / draws / loses / is ignored") or typing a number in an otherwise empty text entry (e.g. declare draw when the same position is repeated .... times"). Untouched squares can be remembered for the entire board as a standard action of the basic system; this never hurts, and castling or special rules that require virginity could use them or ignore them as they want.

Most of the time the user would simply select the rules he wants from the combo-boxes, and never have to see the code this results in. The initial settings of these controls on creation of an entirely new preset could be those of normal Chess, so that in most cases the user would not even have to change them, but can just click 'OK' after having selected board and pieces. Only when a rule is not covered by a standard option (e.g. the counting rules for Makruk instead of the usual 50-move rule) the user would have to provide his own code for it, after deselecting the standard rule.

A simpler way to implement this would be to defer all handling of the standard rules such as mate testing to the basic system, but make its execution there conditional, subject to flags or numeric variables. The rule selection of the user would then only have to result in setting of those variables to the selected value at the start of the game.

Note that when I talk about 'default' code I don't mean code that would always be present or run unconditionally, but code that would be added / enabled unless the user decides he wants to provide something different. Where he should always have the option of having that something be nothing. Just allow exposing to check, capture of your own pieces, ignore mates, never declare draw etc. A non-rule-enforcing preset is the same as a rule-enforcing preset for a game without rules...


H. G. Muller wrote on 2019-11-24 UTC

@Kevin: I was mostly worrying about the existence of non-rule-enforcing presets, which I think we should not have at all. I would have thought that creating such presets would almost never present any problem, as it basically just requires specifying a board size and topology (square/hex), putting a number of piece images on a board in the desired (starting) location, or put them in a 'holdings' next to the board. This doesn't seem to require any special skills beyond those needed to use a computer in general (i.e. using mouse and keyboard). So I am shocked that you say over half of the popular CVs would be beyond your abilities. And I fear the answer to the question of how many rule-enforcing presets you would be able to make for those 107 variants.

I think this is pretty serious, because I consider you as a quite representative example of our target audience. Since you have already investigated the matter, can you give a few examples of CV traits that made you decide creating even a non-rule-enforcing preset was beyond you?

I don't see why it should ever be a problem to define a rule-enforcing preset for a CV with "just sliders/leapers on a rectangular board". Specifying a move on each of the pieces does seem a rather trivial task. And perhaps not even needed for most pieces, as the piece images could have a default move associated with them, so that you only would have to take care of this when you wanted to change that move into something unusual. I would be very surprised is CVs that use the Bishop image (say) would not have it move like an orthodox Bishop in >95% of the cases.


This item is a contest or tournament
It belongs to categories: Orthodox chess, 
It was last modified on: 2019-02-16
 By Greg  Strong. Game Courier Tournament 2019. Chess Variant Tournament to be played on Game Courier.[All Comments] [Add Comment or Rating]
H. G. Muller wrote on 2019-11-22 UTC

Well, perhaps I would be less alarmist when I knew how many of these 1300 presets are actually rule-enforcing. (Or more, as the case may be...) And if the result of a discussion could be that this number could easily be raised to 1300 I would consider that 'productive'. One should never set one's aim too low, nor give up too easily.

That we are volunteers with limited time is all the more reason not to scare people away that could improve something.

And the Bishop conversion rule is not so exotic. It is just an example of a special kind of 'initial move', which does not work per individual piece, but per piece type. Perhaps such a thing deserves to be a standard option offered by a wizard, whenever one defines an initial move on a piece type. Like "can be made by all / can be made only once / can be not made only once".


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