Comments/Ratings for a Single Item

In the winning conditions, I see no explicit mention of checkmate. It does mention that a player without legal moves has lost. So being stalemated is a loss, and consequently being checkmated is a loss too. This would be clearer to Chess players if it explicitly said that either checkmate or stalemate is a loss to the mated player.

Declaring a winner when the game ends after each player has made 100 moves without a capture or a pawn move is unusual. The rule in Chess is that the game is a draw after each player had made 50 moves without a capture or a pawn move. Since this condition occurs mainly in games in which both players have lost sufficient mating material, I wondering about the rationale for giving the win to a specific side.

Having read your notes, stalemate is a win for the stalemated player. Since checkmate has not been mentioned as a specific win condition, I assume that checkmate, as a form of stalemate, is also a win for the checkmated player. Is this intentional? Or did you make an oversight in not mentioning checkmate?

Wow, I didn't even see this until now. I'm sorry. In both checkmate and stalemate, the last move is the one that checkmates or traps the other player, so the player who is trapped loses. With insufficient material or repetition, the last player to capture would win. The winning condition was intended as an experiment in defining a drawless chess game. I have no idea if it would actually be more interesting or not than any alternative.

The other thing I'm not sure about is the zebras. Their jump fits with the other pieces but maybe it's too far for a board this small?

If my name is required I can add that

In the intervening time, we've had submissions from strong community members who do not have their real names displayed on these pages.  I (and I think we?) still have a slight preference for real names, for the encyclopedic nature of the site, but there are many sites now where site-famous people are later referred to as "user xyz of site abc," so maybe it's fine.

Another thing that changed in the time since your submission: the Diagram Designer.  The use of a period to denote a dot on the board (for movement diagrams) has been deprecated; you can replace them with a pound symbol (#), or a few other options.

My thoughts -

Zebra: The Camel is the more common complement to the Knight.  I think a Zebra is OK on a 10x10 board but would be less mobile than the Knight because more moves would be off-board (although a Camel is color-bound so also weaker than a Knight, but I think this is OK because a Bishop is a colorbound piece that could be considered the complement of the Rook.)  Also, if you keep the Zebra, I think you should keep the name as-is.

No Draws: I'm not sure how advisible this is.  The point of Stalemate is to give the player who is behind something to play for.  For repetition and 100-move rule, at a minimum, the written description needs to be clarified.  It currently says the "last player to move" wins, but your comment says "last to capture".  And for 100-move, do you mean "last to capture or push a pawn"?  That would make more sense.  And do you mean 100 half-moves, like the Chess 50-move rule?  Or do you really mean 100 full moves?  I think that would be too much and I don't see any reason to increase it at all.  Personally, I'd scrap all of this and leave all the victory/draw conditions as in orthodox Chess, but that is just personal opinion.

Yes, I should have included pawn moves in that. I meant 100 full moves but that probably is excessive. 
I think I'll just remove the last to move wins stuff from here. I still like the idea but it might make more sense as a separate variant all by itself. 

My reasoning for using zebras rather than camels is that I think it matches the other added pieces better. The gryphon starts with a diagonal step and continues as a rook, and the zebra's move can be described similarly. It begins with a diagonal step and then continues as a knight, jumping over any occupied squares on the way.

I'll try to fix the diagrams and rules.
 

@Fergus,

Trying to edit a preset for this interesting variant by using the fairychess include file I'm almost done, just need to define the function of the Osprey which is a color-bound aanca, first jumping as dabbabah and then sliding outward as bishop. The following diagram shows its move:

I guess the code for Osprey-Range would look like this:

def Osprey-Range mergeall 
  leaps #0 2 0 
  rays where #0 0 2 1 1 
  rays where #0 0 -2 1 1 
  rays where #0 2 0 1 1 
  rays where #0 -2 0 1 1;

and the Osprey-Desc thus: 

"The %s jumps to the second square on the same rank or file, and then slides outward as a bishop."

Could you please tell me the code for such a function? No hurry; when you can spend some time it's fine. Thanks in advance.

Since it's most similar to the Aanca, let's first look at how the code for that piece works:

def Aanca fn (checkride #0 #1 1 1 and empty #0) 
where #0 0 sign - rank #1 rank #0 
#1 
or fn (checkride #0 #1 1 1 and empty #0) 
where #0 sign - file #1 file #0 0 
#1
or checkleap #0 #1 1 0;

The code works backward, as usual. So it first checks whether the move is a one-space orthogonal move. If it is, it returns true immediately. If not, it continues. To calculate whether it makes a legal Aanca move, it needs three coordinates. #0 is the origin, and #1 is the destination, but it also needs the coordinate for the space on which it changes direction. Unfortunately, variables cannot be assigned in functions. The next best thing is to use a Lambda function that can take arguments. These appear in parentheses after the fn operator. Each one is the same, but each one gets fed different arguments. The second argument is always #1, which is the destination space. The first argument is the space where the move changes direction. Since each destination space falls into one of four quadrants, and there are two possible paths to the destination through a particular quadrant, this information is used to reduce the paths that need to be checked to two.

It first checks whether the move is going left or right, and based on that, it selects the space to the left or right of the origin space as the turning space. It then makes sure it is empty and that there is a legal Bishop move from it to the destination space. If that fails, it checks whether the move is going forward or backward, and based on that, it selects the space ahead or behind the origin space as the turning space. It makes sure this space is empty, and if it is, it makes sure there is a legal Bishop move from that space to the destination. If there is, it returns true, and if there is not, it returns false. I expect that the piece you want can be done with only slight modifications to this function.

How should the underlined parts be read (interpreted)?

def Aanca fn (checkride #0 #1 1 1 and empty #0) 
where #0 0 sign - rank #1 rank #0 
#1 
or fn (checkride #0 #1 1 1 and empty #0) 
where #0 sign - file #1 file #0 0 
#1
or checkleap #0 #1 1 0;

Particularly, what do the underlined  0 's mean?

def Aanca fn (checkride #0 #1 1 1 and empty #0) 
where #0 0 sign - rank #1 rank #0 
#1 
or fn (checkride #0 #1 1 1 and empty #0) 
where #0 sign - file #1 file #0 0 
#1
or checkleap #0 #1 1 0;

The underlined parts are arguments to where, which takes three arguments. The first argument, which you haven't underlined, is the starting coordinate. The next one is a number of files, and the last one is a number of ranks. These values may be negative or positive, and this determines direction. Using these values, where returns the coordinate that is so many files and ranks away in the given directions. This is being used to calculate the coordinate of the turning square, which is one of the arguments for each of the Lambda functions. This uses sign, which returns -1, 0, or 1, depending on whether a value is negative, zero, or positive. When 0 comes first, it will typically be calculating where #0 0 1 or where #0 0 -1. Where 0 is last, it will typically be calculating where #0 1 0 or where #0 -1 0. When the destination is on the same file or rank, and it is not a Wazir move away, it may sometimes return where #0 0 0, which will be the starting space. Since there is no Bishop move to a space on the same rank or file, the function will return false for such a destination, which is correct. For potential moves, it will return false even earlier, since that space will still be occupied.

Thanks. I think we are close to finding the solution!

Then the question is how do we get the where operator returns the 4 options:

where #0 2 0

where #0 -2 0

where #0 0 2 

where #0 0 -2

Is there any other digit to use instead of 0 that fulfills the desired purpose? I mean the zero that I previously underlined.

What is easy to deduce is that the first backward line of code should look like this:

or checkleap #0 #1 2 0;

Is my assumption about the Osprey-Range definition correct?

def Osprey-Range mergeall 
leaps #0 2 0 
rays where #0 0 2 1 1 
rays where #0 0 -2 1 1 
rays where #0 2 0 1 1 
rays where #0 -2 0 1 1;

The range function looks correct. Where the Aanca function calculates 1 or -1, you want yours to calculate 2 or -2. The simplest way is to multiply the return value of sign by 2.

With the following code I have made some progress because the piece already can make the desired legal moves:

def Osprey fn (checkride #0 #1 1 1 and empty #0) 
  where #0 0 * 2 sign - rank #1 rank #0 
  #1 
  or fn (checkride #0 #1 1 1 and empty #0) 
  where #0 * 2 sign - file #1 file #0 0 
  #1
or checkleap #0 #1 2 0;
 

def Osprey-Range mergeall 
  leaps #0 2 0 
  rays where #0 0 2 1 1 
  rays where #0 0 -2 1 1 
  rays where #0 2 0 1 1 
  rays where #0 -2 0 1 1;

However something must be wrong since the program allows the Osprey to be moved as ferz. What do you think is the cause?

That looks correct.

Yes, but then how to explain that the program allows moving the piece like Ferz?

I'd guess it's seeing a 2-leap followed by a bishop move inward as legal?  And that doesn't matter for the Aanca because those same squares can be reached legitimately by a shorter path.

Interesting deduction, Ben. Let's see what Fergus thinks.

You can screen those out with a line that rejects ferz moves. Here is a revision:

def Osprey fn (checkride #0 #1 1 1 and empty #0) 
  where #0 0 * 2 sign - rank #1 rank #0 
  #1 
  or fn (checkride #0 #1 1 1 and empty #0) 
  where #0 * 2 sign - file #1 file #0 0 
  #1
and not checkleap #0 #1 1 1
or checkleap #0 #1 2 0; 

Set. Problem solved. Thank you very much for your help, Fergus.

There is an error in the article probably. When castling is described it says that the king moves 3 squares but this can't happen when castling short as the rook is in the way.

That would not be considered a problem in Chess960, so why should it be considered a problem here? Just treat them as Fischer castlings. The Interactive Diagram I made for this does allow you to move the King on top of the Rook, and interprets that as a castling.

Ok!

The reason for castling being the way it is is that I think it makes more sense if the king ends up closer to the edge of the board.

Interestingly this variant put 3 additional pieces on the decimal chessboard, 3 additional pieces that are, as the matter of fact, old known pieces! Indeed the 3 of them are found in the Grant Acedrex from King of Castile Alfonso X's codex published in 1283.

The Gryphon is the Aanca of the Spanish text, an Arabic word designating an "Elephant Bird", a very big legendary eagle of the oriental tales, able to carry an elephant. Murray translated, a bit wrongly, as a Gryphon (which is another legendary animal).

The Osprey is the Unicornio of the Spanish text, which according to the original illustration designated a Rhinoceros. Consider that in 1283 not a lot of people new what a rhinoceros was and it was identified with the legendary unicorn. I like the idea of a Rhinoceros for this piece that goes deep inside the opposite defensive lines.

The Zebra is the Zaraffa of the Spanish text, obviously a Giraffe, considering that, again in the 13rd century, this beast was a bit frightening for those who had the chance to have seen one. Murray and some others after him had another interpretation of the described move, a step (5,2) instead of a step (4,3) which was a misunderstanding.

http://history.chess.free.fr/acedrex.htm

I also use Eagles, Rhinoceros and Giraffes in Zanzibar but on a 12x12 board.