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Steven Streetman wrote on Fri, Oct 29, 2010 07:38 PM UTC:
Would anyone like to play a game of Spartan Chess?

I have submitted this chess version to Chess Variants and hope it will soon be posted.
In the meantime you can visit my web site for the rules: SpartanChessOnline.com

Spartan Chess Features:
• A Persian army (white) identical to that of orthodox chess
• A Spartan army led by two Kings
• Spartan pawns (hoplites) that move differently than orthodox pawns
• Spartan pieces that move differently than any found in orthodox chess
• No opening book
• No end game studies
• Asymmetric play and feel
• Can be played with a standard chess set
• Different victory conditions for both sides

So be warned, it is different. We can play via email and I can send a “snapshot” of the board after each of my moves.
I am happly to play as either Black (Spartan) or White (Persian).

Set Up

You may contact me at: [email protected]


H. G. Muller wrote on Fri, Oct 29, 2010 10:15 PM UTC:
I am curious to the winning conditions. They are not clear to me. Spartan Kings can venture into Check. I suppose they can be captured when they do. So they might be reduced to a single King. Do they lose by normal checkmate in that case?

What do you mean by evading the 'duple check'? Is it enough to evade one King, so that it is turned into a single check (which you are allowed to move into or stay in from other positions)? Why wold you have to evade at all? The opponent can never capture two Kings at the same time.

About your piece values: I think you underestimate the R+N and B+N compounds. When Q=9 they shoud be 8.75 and 8.25. The other two are about equal to a Knight (slightly weaker). In the FIDE army B=3.5 is only the first of a pair; the second should be equal to N.

A Commoner would also be slightly weaker than N in tactical value; I don't know what the check immunity buys you extra.

Steven Streetman wrote on Sat, Oct 30, 2010 01:09 AM UTC:
-----From the rules------------
4.12 Persian Victory - The Persian (white) wins once one of the Spartan Kings is captured and the remaining Spartan King is checkmated or when both Spartan Kings are placed under simultaneous attack (duple-check) and neither King can be removed from attack on the next move (see 4.4 Duple-Check and Mate).

4.4 Duple-Check & Mate If both Spartan Kings are placed under simultaneous attack this is called duple-check (d+). It is illegal for the Spartan to make a move that will place his Kings in duple-check. The Spartan loses if on his move he is unable to escape duple-check in which case the game ends in a duple-checkmate (d#).
--------------------------------
As you can see the Spartan need merely to remove one King from duple-check.

As for the values of pieces.... boy oh boy do opinions vary and I am always open to learning what people have to say on the subject. On another site there is a pretty detailed analysis.

The beginning of this analysis shows values for the Queen: 8.75, the Chancellor (my General): 8.25 and the Archbishop (my Warlord): 6.50. At the end he shows the calculations done by Reinhard Scharnagl on a 8x8 board as Queen: 8.9531, the Chancellor: 8.3750 and the Archbishop: 6.5781.

I certainly did take liberties in rounding the figures off in my presentation which can be found here: http://spartanchessonline.com/values.html which I imagine from your comments you may have already looked at.

As for duple-check (I could not use double check since this is a term already understood in orthodox to mean something else) the balance and 'fun' of the game was improved in version 1.06 when duple-check was introduced. Once the minor pieces are traded off the Spartans can plod across the board shepherding the forces with their 2 Kings. Once duple-check was introduced there were some very dynamic games. The Spartans in the center of the board with the White Queen and rooks circling them from both flanks and the rear ranks duple-checking the Spartans frequently and eventually being able to work out a White win.

As for the value of 'simple' check immunity for the Spartan, that is a puzzler. It's worth something, maybe a lot. I do know that the first time a Spartan King played the move Kc4-b3+ (since it was then next to the White King) we did a lot of laughing.

H. G. Muller wrote on Sat, Oct 30, 2010 10:39 AM UTC:
OK, I see now that I missed the 'Complete' rule description on your site;
I had only looked at the summary. I was of course interested to see how
Fairy-Max could be generalized to handle this variant. Ithin this should
not be too difficult: it should keep a running count of the number of Kings
(this is easy to add, in fact it can keep counts for any piece type), and
then count the number of Kings that can be captured (being careful to count
two captures of the same King as just one King), and only consider it a win
if all Kings can be captured from the same position.

Am I correct in assuming that the following position is draw due to
stalemate?

8 . . . . . . R .
7 . . . . . . . .
6 . . . . . . . .
5 . . . . . . . .
4 . . . . . . . .
3 . . . . . . . .
2 . . . . K N h h
1 . . . . . . k k
  a b c d e f g h
  black to move

I am aware of the 'analysis' of piece values by the person that cannot be
mentioned here. This is just educated guessing, though, and in practice
this turns out to be useles for determination of piece values. The
Scharnagle theory is still-born, as it even does not get the orthodox
pieces rights: it values Queen exactly equal to Rook + Bishop, whle it is
well known that there is more than a Pawn difference between the two. Fact
is that between equal players, having A+P in stead of Q in an otherwise
complete FIDE army, gives you the better end of the score. (As I reported
in the forum of the website with the forbidden name.)

Steven Streetman wrote on Sat, Oct 30, 2010 02:27 PM UTC:
Yes indeed, the position you present with Spartan Kings at g1, h1 is a draw
via stalemate. With Black to move only 1 King is under attack and both
possible Spartan moves: Kg1-f1 and g2-f1 are illegal since both result in
duple-check.

---------------------------------
Just a note: At some point the King at h1 came under attack by the Knight
at f2. If this happen when white move the Knight from d1 we record the move
as Nd1-f2 !+ . The !+ meaning the attacked King is not in check. We record
it this was just for purposes of clarity.

As for your comments concerning Scharnagle’s analysis, my experience-based
guts certainly tell me you are correct. As for people we cannot mention,
that sounds like something good to know.

Still I ponder the relative value of Spartan pieces in general and the
Colonel and Lieutenant specifically. Both leap like a Knight and hit the
same number of squares so it seems they all should be roughly equal. But on
the other hand they don’t have as many safe checks as a Knight (important
in many evaluation theories). But as you point out experience is the best
guide in so complicated a subject and these two Spartan, in play seem about
equal to a Knight.

H. G. Muller wrote on Sat, Oct 30, 2010 10:02 PM UTC:
I succeeded in havng Fairy-Max play Spartan Chess, sort of. The only
problem left is promotion: Fairy-Max always promotes to the same piece,
which I set to Queen. So the Spartans can end up with a Queen. I don't
expect this to have any effect on play-testing for piece values, as Queen
and R+N are nearly equally strong, and a promotion is usually decisive with
either one of them.

If you (or anyone else) wold like to try: I prepared a pre-configured
WinBoard + Fairy-Max pakage, including a shortcit for playing Spartan. You
just have to unzip it in C:\Spartan (I guess C:\ actually as the Spartan
folder is already in the zip archive), and it should be ready to play. It
can be downloaded from:

http://hgm.nubati.net/Spartan.zip

A first impression is that the Spartans have the upper hand over FIDE, but
not overwhelmingly so. (I have seen draws, and sometimes FIDE even wins, at
40 moves/min.)

Btw, I don't understand why you would want to complicate the check notation. When only one King can be captured, you are simply not in check. Only duple check is check, in the sense that null-moving would now lose the game, and you have to evade.

Steven Streetman wrote on Sat, Oct 30, 2010 10:19 PM UTC:
Great! And thanks!
I have a place to go this evening. Tomorrow I will give it a try.

Check notation…
Whoops…
You do have a good point about the check notation. It seems that our
notation evolved this way through play testing various versions. 

I will think about it and if I cannot come up with some really really good
reason why I should keep this more complicated notation, then I will
simplify the check notation as you have suggested. Thanks for your
observation.

Steven Streetman wrote on Sat, Oct 30, 2010 10:53 PM UTC:
What a fine job you have done Mr. Muller and thanks again. I could not wait
so downloaded your zip file and ran part of a game.

The positions of the Lieutenants (elephant model) and the Colonels
(rook-like model) need to be swapped. All else looks fine.

I look forward to digging into this tomorrow.

btw - I was looking at fairy-chess piece notation at:
http://en.wikipedia.org/wiki/Fairy_chess_piece. I was preparing to look at
Fairy-Max and wanted to have some set of notation in mind before I began. I
suspect your notation is different. For the 3 Spartan Chess pieces not
already documented on this page I came of with this which I think is
correct but perhaps not relevant at this point:

• Colonel: 	1+, ~2+
• Lieutenant:	1X, ~2X
• Hoplite:	o1X>, c1>, io~2X>

Steven Streetman wrote on Sun, Oct 31, 2010 03:00 AM UTC:
Easy, just swapped changed the starting locations in the Spartan.ini and I
am in good shape. So easy even I could do it!

H. G. Muller wrote on Sun, Oct 31, 2010 09:58 AM UTC:
Indeed, what Fairy-Max uses to define the pieces in its fmax.ini file is not
so much a notation, as well a direct reflection of how its move-generator
tables are to be filled. To equip it with some sort of compiler for a more
user-friendly format is something that never got off the to-do list. :-(

Basically it is just a list of step vectors on its internal 16x8 board,
which has the additional complication that white plays 'downstream' (so
-16 is one step forward, etc.). This has the advantage that any form of
asymmetry (also left-right) can be handled without extra provision. But it
has the disadvantage that the common case of totally symmetric pieces still
requires a cumbersome enumeration of each individual direction. Like to
define a Knight you would need +14, +31, +33, +18, -14, -31, -33, -18. It
would be nice to have some meta-symbol that would allow you to abbreviate
this to something like 18* or (2,1)*.

Apart from specifying each direction, you also have to specify what the
move can do in each direction (capture, non-capture) even in the
overwhelmingly common case where you can do both. So the common case is
that you have an enumeration now of STEP,RIGHTS codes, where RIGHTS equals 3
(for slider) or 7 (for leaper). For divergent pieces the RIGHTS can be 1 or
2 lower, depending on if capture or non-capture is forbidden. RIGHTS codes
larger than 7 are only needed for the more uncommon case of two-stage moves
(like hoppers or lame leapers). There you would have to specify (in the
high digit) another set of rights for the second stage of the move, with
very obscure encoding.

Special cases are castlings and initial pawn double pushes. I use an
otherwise useless RIGHTS code 4 for that (which in the system would
indicate a leaper move that can neither capture nor non-capture). Fairy-Max
takes that to mean the same as 0 (indicating a step that can't do anything
but is not the last stage of the move, so that it is still useful as an
intermediate step of a lame leaper, or a Grasshopper on the way to its
platform), except that you are only allowed to do it with a virgin piece.
So the double push of a Pawn is actually implemented as an independent
lame-leaper move added to the Pawn.

E.p. capture of pieces that did such a special virgin lame-leap was
hard-wired in Fairy-Max, and this is one of the things I had to change for
Spartan Chess. With the usual definition of the Pawns (either FIDE or
Berolina), the Hoplites could be e.p.-captured, and were forbidden to move
to a square just jumped over by a FIDE Pawn (because this was interpreted
as an attempt to e.p. capture the FIDE Pawn, and Berolinas are not allowed
to capture diagonally...). So I requisitioned some bits that would be
meaningless in this case from the high-order digit of the RIGHTS (if the
low-order digit is 4), to indicate that the e.p. square should not be set,
and to indicate if the double-push can be made even if the intermediate
square is occupied (for the Hoplites), and added some C-code to perform 
the required actions in response to these bits.

H. G. Muller wrote on Sun, Oct 31, 2010 11:04 AM UTC:
I uploaded a corrected version of the Spartan Fairy-Max package:

*) It corrects the initial setup.
   (Note that this depends on a subtle interplay between the definition
    of the initial position in Spartan.fen, the mapping of characters
    onto piece bitmaps defined in Spartan.ini, and the mapping of
    piece names onto moves in fmax.ini.)
*) I changed Fairy-Max' internal encoding of royalty back to negative
   values, as the previous patch eluded some King-Safety tests, leading
   to frivolous play with the King (even for white) in the middle-game.
   This means the piece value of a capturable King now has to be indicated
   in the fmax.ini as the negative of the intended value.
   (Downside of this is that the rule that you only win by capturing
    the opponent's last royal piece is now always applied, and you cannot
    define variants anymore where the loss of the first royal piece
    would mean the end. But as I actually don't know such variants,
    while there are several 'extinction Chess' variants, this seems
    a small price for something good and generally useful.)

H. G. Muller wrote on Mon, Nov 1, 2010 09:25 AM UTC:
I let the computer run games all night (at 40 moves/min), and the first
results indicate that the game is biased in favor of the Spartans: they
score some 70-75%. For comparison: in FIDE Chess Pawn odds results in a 68%
score, so it seems the advantage is slightly more than a full Pawn.

Noticeable is the low draw rate: only around 15%. (In FIDE this is ~32%.) I
guess the end-game value of the Hoplite is larger than that of a FIDE Pawn,
making it much more difficult for the Persians to draw games where you are
a Pawn (Hoplite) down. For instance, KHK has far fewer draw positions than
KPK. (On a cylinder board it would have none at all; you are dependent on
the Hoplite running into an edge in order to stop it, and even unprotected
Hoplites cannot be approached to capture them, and even can advance through
zugzwang.)

Steven Streetman wrote on Mon, Nov 1, 2010 08:20 PM UTC:

FAVORS SPARTANS
I am glad that we are playing so many games of Spartan Chess via computer. Just as you said, there is a learning curve to playing this game and it’s hard for a few human play testers here to play enough games to determine if this variant is balanced. It looks, in fact, like some of our recent changes might have made if unbalanced in favor of the Spartans.

Yes, in computer play it does certainly seem that Black, the Spartans, have the edge.

ADDRESSING PLAY BALANCE
There is one thing I can do to try to address this imbalance without changing the pieces and that’s to alter the Spartan setup. The current set up is among the most powerful possible with the Colonels in the center and Lieutenants on the far flank.

I am currently trying this setup for the Spartans which is, I believe, is not as strong:
c l k g w k l c

If this does not balance the game there are a few other candidate set ups and a few small changes I can make to the Spartan pieces which have all been tried before in play test:
a) Remove the horizontal move from the Lieutenant
b) Remove hoplite first move jump making them just like berolina pawns in all respects.
c) Reintroduce concept of pinning hoplites, that is where an enemy pawn or pieces in directly in front of a hoplite the hoplite my still capture but my not move (deals with hoplite zigzagging through Persian pawn formations. Hoplites can still dash for the side of the board away from a Persian King.

QUESTION When I run match play for 20 games for example, I cannot quite determine the number of wins for Black. I am using the record in the Winboard Application title bar which might be 7-4-2 after 13 games and 4-7-3 after 14 games with the 14th game being a draw. What is in the title bar of the Winboard Application is the player record, not the black/white record. So it flip-flops after each game. How do I determine the record for Black? I am not so familiar with this application yet.

Note: I am been just recording the games one at a time while doing other things and writing down the result.


H. G. Muller wrote on Mon, Nov 1, 2010 10:44 PM UTC:
The easiest way is to start WinBoard with the options /mm
/sameColorGames=20. (You could add these on two lines in spartan.ini file.)
Then the same side always has white, so the player record will be the same
as the white-black record. Unfortunately this cannot be done from the menu
yet, the ' Machine Match' menu item is equivalent to /mm /matchGames=N,
which will always alternate the color.

I have made some progress upgrading Fairy-Max. It still always promotes to
the same piece, but that piece can now be different for white and black. So
the Spartans can promote to General. I already uploaded the sources to my
repository at hgm.nubati.net. I will make a Windows compile tomorrow.

Steven Streetman wrote on Tue, Nov 2, 2010 12:16 AM UTC:
Changes
I have added those 2 lines to the spartan.ini file as I am running 20 games! Yay! I am using this configuration of Spartan pieces:
l g c k k c w l

We will see how that goes.

STUDY
I have been looking over fmax.ini. Iam looking at this partion that appears to be about Spartan chess:

// Spartan Chess, where black has a different army from white's orthodox FIDE, with two kings
Game: fairy
8x8
6 4 5 7 3 5 4 6
11 9 3 10 10 3 8 11
p:74 -16,64 -16,6 -15,5 -17,5
h:74 15,E4 17,E4 16,5 15,6 17,6
k:-400 1,34 -1,34 1,7 16,7 15,7 17,7 -1,7 -16,7 -15,7 -17,7
n:259 14,7 31,7 33,7 18,7 -14,7 -31,7 -33,7 -18,7
b:296 15,3 17,3 -15,3 -17,3
R:444 1,3 16,3 -1,3 -16,3
Q:851 1,3 16,3 15,3 17,3 -1,3 -16,3 -15,3 -17,3
w:790 15,3 17,3 -15,3 -17,3 14,7 31,7 33,7 18,7 -14,7 -31,7 -33,7 -18,7
G:814 1,3 16,3 -1,3 -16,3 14,7 31,7 33,7 18,7 -14,7 -31,7 -33,7 -18,7
l:270 15,7 17,7 -15,7 -17,7 30,7 34,7 -30,7 -34,7 1,6 -1,6
c:250 1,7 16,7 -1,7 -16,7 2,7 -2,7 32,7 -32,7

I am guessing that the first number after the colon for each piece is the weight of the pices and the pairs of numbers that follow movement vectors. If that is correct then I could make some changes to the Spartan pieces to see how that impacted balance. Problem for me is I don’t know for sure if that is what this is and if these are movement characteristics I am not sure how to change them.

QUESTIONS
So, two questions

1. Do the number pairs, such at 1,7 in the last line for the colonel, define the piece movement?

2. If the answer to #1 is yes, is there some documentation on this? I don’t see a help file for Winboard. If I were to find and download a fresh copy of winboard would there be a help file explaining the layout of this file?

Steven Streetman wrote on Tue, Nov 2, 2010 02:30 AM UTC:
A friend of mine gave me some insight into the movement vectors. For
movement the first number is a direction and the second number a movement
type. 

For the Colonel therefore:
1,7: 1 = 1 square forward and 7=jump movement type
2,7: 2 = 2 squares forward and 7=jump movement type

I will see if I can figure the rest of it out in the morning.

Steven Streetman wrote on Tue, Nov 2, 2010 03:11 AM UTC:
Here is what I think I have deduced so far…

For second part of vector:
3 = Any distance slide to move or capture
5 = capture only
6 = move only
7 = Jump to move or capture
64 = first move only, movement no capture
E4 = first move only, jump, no capture

Now I just have to figure the first part, the destination square.

H. G. Muller wrote on Tue, Nov 2, 2010 08:39 AM UTC:
The early part of the fmax.ini file contains a full description of the vector and move-type encoding. The version you have needs a bit of updating because of the features I added to support Spartan Chess, however. An excerpt: ----------------------------------------------------------------- The board steps are encoded as follows: ^ toward 8th rank | -52 -51 -50 -49 -48 -47 -46 -45 -44 -36 -35 -34 -33 -32 -31 -30 -29 -28 -20 -19 -18 -17 -16 -15 -14 -13 -12 <-- -4 -3 -2 -1 start 1 2 3 4 --> towards h file to 12 13 14 15 16 17 18 19 20 a-file 28 29 30 31 32 33 34 35 36 44 45 46 47 48 49 50 51 52 | v towards first rank ---------------------- snip ------------------------------------- In the last hexadecimal digit: 1 capture allowed (of enemy piece; own pieces always block a move) 2 con-capture allowed (i.e. we can move here if the square is empty) 4 leaper, i.e. move terminates after one step (as opposed to slider) 8 hop over non-empty square (normally occupied squares terminate a move) Bits set in the forelast digits TOGGLE the corresponding bits in the last digit. For hoppers when they hop over something, for the other pieces after every step (so for normal pieces, better not set those bits!). The digit before that can only be 0 or 1; a 1 indicates the board should be treated as a cylinder, pieces crossing the right edge re-entering the board at the left, and vice versa. The higher-order bits toggle corresponding bits in the step vector, to allow zig-zag paths. Better not set those either, if a straight path is desired. Useful bit combinations for the last digit are: 3 normal slider 7 normal leaper 6 leaper that only moves (e.g. Pawn straight ahead) 5 leaper that only captures (e.g. Pawn diagonal) 1 slider that only captures 2 slider that only moves 0 pass through (for testing emptiness by Xiangqi Horse and Elephant) 4 reserved for skip-step of Pawn double move and castling 8 skip to hopper platform (1st part of Grasshopper move) A non-capture before hop (1st part of Cannon move) C must hop immediately

H. G. Muller wrote on Tue, Nov 2, 2010 09:19 AM UTC:
To get back to Spartan Chess:

I doubt if shuffling the initial setup can create enough difference. I
agree that the proposed array seems the best, but as all pieces can jump
over the Pawns it is not terribly critical where you put them. The rule of
thumb is that 3 tempi is a Pawn, and we need to bridge more than a Pawn.
Even if you would make the Lieutenants and Colonels obstruct each other by
having them jump to the same square, that would only take 2 moves to
correct. (And a second move with the same piece to evacuate the square for the other might even be partly useful.)

Similarly, the sideway Lieutenant move is not worth very much. I tested the value of such moves on Bishops once, and there was almost no benefit compared to a plain Bishop, (about 0.25), as long as these came in pairs. The double Hoplite push will be worth something, but as the Spartans are not really dependent on Pawn moves for their development, I doubt it will be much. (It would be interesting to test it, though.)

Having artificial rules like the pinning of Hoplites is something I
generally dislike. Let me suggest two more options for trimming the Spartan
strength:

1) reduce the value of the General or Warlord, by using the corresponding
crowned slider rather than the knighted one. I am currently running games
whwer I replaced B+N by B+K, which should be worth R+0.25. The Persians are
leading there 24-18 (so not yet significant, but quite a change from what
it was). If this is too much, the R+N could be replaced by R+K, which
should be around 7.

I think the main problem is that the Hoplites are better in the end-game
than FIDE Pawns, so that the Persians need stronger piece material to hold
them back. Normally, trying to balance a significant Pawn advantage with
pieces unbalances a game, because in the middle-game the Pawns are
irrelevant, and the stronger pieces lead to quick checkmates. You can
always balance the over-all result to 50%, but you will get a game where
one side must inflict a quick middle-game checkmate, or he will be doomed
with certainty in the end-game. This is usually not very interesting. In
Spartan Chess, however, a quick middle-game mate is not easy because of the
dual King. So we can afford much larger strength differences in piece
material than usual without running into this problem.

This brings me to the second proposal:

2) If the problem is that Hoplites promote much easier than FIDE Pawns in
the end-game, it might be possible to offset this by strongly reducing the
value of the piece they promote to. So much, that a single promotion is no
longer decisive, but you need two. (Assuming that it is about as difficult
to promote two Hoplites as it is to promote a single FIDE Pawn.) So perhaps
it would work if the Hoplites are forbidden to promote to G or W. The
preferred choice than probably would be C (which has mating potential).
This would also provide more incentive to promote to K, which might be
stronger than C, but is so much weaker than G or W that the possibility to
promote to K in Spartan Chess in the current rules is of as much practical
relevance as promotion to B in orthodox Chess (namely none...).

H. G. Muller wrote on Tue, Nov 2, 2010 01:36 PM UTC:
I posted the updated WinBoard/Fairy-Max package at
http://hgm.nubati.net/Spartan.zip . 
I also included the WinBoard help file, this time. (But don't look there for info on Fairy-Max; WinBoard is an independent project, and Fairy-Max is just one of the many hundreds of engines that can run under its control.)

This version of Spartan Chess is configured for having black promote to
R+N, and white to Q. (I had to fix a lot of bugs in WB to get that working:
it was not prepared for white and black playing with different piece sets
at all.) The explanation on the encoding in fmax.ini is fully updated. (And
with this version of Fairy-Max, the order of the piece defintions is more
important than it was before, but also this is explained.)

In the mean time, the test with the B+N replaced by B+K has reached 100
games, and white was leading by 54%. Now this is close to the normal white
advantage (which is 53-54%). So after this test is done (i.e. 400 games), 
I will try it with a start position where black has the first move.

Steven Streetman wrote on Tue, Nov 2, 2010 05:53 PM UTC:
We have messages passing each other :)

Shuffling Pieces
Yes, that is the way it is working out. Changing the back rank changes the balance only very slightly if at all and certainly not enough.

Hoplite pin
We play tested pinning hoplites and removed it for pretty much the reasons you stated, unnatural. This is now a dead consideration.

Weakening General and/or Warlord
I have shuffled the starting position back to one more favored early ones:
c l k g w k l c

Based on your suggestion to reduce the power of the General and/or Warlord I have reduced the power of both of them and running games with them having these characteristics:
General = Rook + Afil
Warlord = Bishop + Dababa

If this is still too strong then the jump can be blocked for the Afil and Dababa portion of the move. Or if this is too weak then only one might be changed rather than both. Alternatively one or both might better as the crowned versions you are testing.

From among the Royal versions of the pieces you suggested, which gave rise to my thinking about these, perhaps we will find a variation that is sufficiently balanced. Play testing for balance will be the judge.

Hoplite Promotion
I understand and have experience your point. I am tempted to say lets go ahead and try your suggestion, promote to a Colonel or King.

Steven Streetman wrote on Tue, Nov 2, 2010 06:12 PM UTC:
54% winning advantage for white sounds great. 

If I understand correctly
General = R+N
Warlord = B+K

I will download your new version and find out.

Also, it seems you have a faster computer than I do :)

H. G. Muller wrote on Tue, Nov 2, 2010 07:07 PM UTC:
Well, after about 200 games the score has crept up to 57% for the Persians.
(Note that the download still uses the rules of your website!)
I am playing 40 moves/min, which makes the average game take 3 min. So I
can do 20 games/hour, 480 per day. But I am playing with ponder off, so it
takes only a singe core to play a game, and I have a dual. So I am running
two matches in parallel. :-)

On the other core I started the test with promotion to Colonel. It hardly
seems to matter. After 60 games, the Spartans are still leading by 70%. So
I guess we can scratch this idea, and I probably won't finish the run.

As the Persians are now winning, weakening the Warlord to a Crowned Bishop
was too much. When  look at the games, it is also awkward: the Spartans
have very much trouble in the standard setup to develop it. Fairy-Max is
reluctant to move away the f-Pawn (Hoplite) because it is shielding a King
and also reluctant to play Hg7h6, because it puts a Hoplite on the edge.
And after Hg7f6 it still blocks the Warlord after Wg7. So apart from the
fact that the intrinsic difference between B+N and B+K is much larger than
that between R+N and R+K, it also does not make good use of the B+K.

So the next thing I will try (on the other core) is to keep Warlord as B+N,
and make the General R+K. This should work much more smoothly: moving the
b-Hoplite immediately opens a file for it, so there should be no problem
developing. Promotion can then be to B+N Warlord, which, based on the test
with Colonel-promotion, should cause no weakening at all. An alternative would be to equip the B+K piece with some extra moves that help in development, e.g. a (2,2)-jump, or when that is too strong, only as a non-capture. But that makes it a bit of a weird piece, so I would prefer the clean R+K if it does the job.

When I have a setup that is fairly balanced, I will start running tests
with some pieces deleted from the opening array, (preferably in pairs, to
increase sensitivity), like Colonels on one side and Knights on the other,
to see how this changes the score (i.e. to whom such a trade would be
favorable). This to verify if the values I programmed into Fairy-Max are
close enough to reality. If not, it would be wise to repeat the tests with
corrected piece values in a second iteration. My experience is that
slightly wrong values hardly affect the score, as long as both sides share
the same misconception. (E.g. it does not matter if you program the value
of the Bishop higher or lower than that of the Knight: two Bishops will
beat two Knights by ~58% in both cases.)

Steven Streetman wrote on Tue, Nov 2, 2010 08:12 PM UTC:
Setup
With the set up of the back rank not mattering so much I am standardizing
on using the setup in the rules: l g k c c k w l

Download Fiery-Max
I just downloaded Fiery-Max and it has the Warlord as uncrowned B+N and the
General the same way, that is R+N. I will change the General to a crowned
general by changing fmax.ini and start running games.

Weakening General and Warlord
My weakening both the the General to a (R + Afil) and the Warlord to a (B +
Dababa) is certainly too much a shift in favor of the Persian.

Knife Edge
It does not take much to change the balance a lot, just has to be the
change.

Steven Streetman wrote on Tue, Nov 2, 2010 08:36 PM UTC:
Relative Strength
I meant to pose this question in my last post but it slipped my mind. What
do you have to say about the relative strength of these two sets of
pieces?
1. Crowned Rook: R + K vs. R + Afil (jumps 2 squares diagonally)
2. Crowned Bishop: B + K vs. B + Dababa (just 2 squares orthogonally)

At first blush I though the jumping piece in each pair would be stronger
but now I am not so sure.

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