Comments by Reinhard Scharnagl

There is a new program Smirf (still beta) playing not only 8x8 classic
chess and Fischer Random Chess but also 10x8 Chess variants based on the
Capablanca piece set. It supports also Janus chess and the Capablanca
Random Chess (or FullChess) variant proposed by myself since several
months:

CAPABLANCA RANDOM CHESS (2004-Nov-26) Proposal 

This definition of CRC should cover the following goals:

a) creating an interesting drosophila for chess programmers 
b) using Capablancas 10x8 Chess board geometry 
c) using Capablancas piece set (incl. archbishop and chancellor) 
d) applying rules aligned to Fischer Random Chess 
e) avoiding conflicts to any claimed patents 

The CRC rules are: 

a) creating a starting position (one of 48.000): 
 1) the bishops have to be placed upon different colored
  squares; same rule applies to the implicite bishop pieces:
  queen and archbishop (aligned to FRC)
 2) the king always has to be placed somewhere between the 
  rooks to enable castlings (aligned to FRC)
 3) use only such positions without unprotected pawns (Chess)

b) describing a method of generating starting positions on 
   free squares by using a dice or random number generator: 
 1) select queen or the archbishop to be placed first (2x)
 2) place the selected 1st piece upon a bright square (5x)
 3) place the selected 2nd piece upon a dark square (5x)
 4) one bishop has to be placed upon a bright square (4x) 
 5) one bishop has to be placed upon a dark square (4x) 
 6) one chancellor has to be placed upon a free square (6x) 
 7) one knight has to be placed upon a free square (5x) 
 8) one knight has to be placed upon a free square (4x)/2 
 9) set the king upon the center of three free squares left
11) set the rooks upon the both last free squares left 
12) this establishes White's first row, the Black side 
    has to be built up symmetrically to this 
13) place ten pawns similar to traditional chess in a row 
14) skip this position if it has unprotected pawns or not
    at least three positions in line 1 differently filled
    compared to Gothic Chess, this finally gives about
    21.259 distinct starting arrays.
   
c) nature of (asymmetric Fischer-) castlings:
 1) castlings are (like in traditional chess) only valid
  if neither the affected king or rook has been moved, or
  there would be a need to jump over any third piece, or
  the king would be in chess somewhere from his starting
  position to his target field (both included). Therefore
  all squares between king and its target square (included) 
  have to be free from third pieces, same applies to the
  way the rook has to go to its target square.
 2) the alpha-castling (O-O-O, White's left side):
  like in FRC the king will be placed two rows distant
  from the border (here c-file) and the rook at the next 
  inner neighboured square.
 3) the omega-castling (O-O, White's right side):
  like in FRC the king will be placed one row distant
  from the border (here i-file) and the rook at the next 
  inner neighboured square.

d) performing castlings:
 within a GUI try to move the king upon the related rook
 or at least two squares into that direction; manually:
 1) move the king outside of the board
 2) move the rook to its end position (if need to)
 3) move the king to his end position

e) extended FEN encoding:
 1) the extended FRC-FEN could be used as a base
 2) 'a'/'A' are used to identify archbishops
 3) 'c'/'C' are used to identify chancellors
 4) '9' is used to mark nine empty fields
 5) '0' is used to mark ten empty fields
 6) if a castling enabled rook is not the most outer one
  at that side, the letter of his file has to be placed
  immediately following his castling marker symbol, where
  'q'/'Q' are used for the alpha-, 'k'/'K' for omega-side.
 
f) engine notation rules for castling moves:
 According to UCI convention the castling moves should be
 written by using both coordinates (source and target field)
 of the involved king. But there are castlings, where the 
 king does only one or none simple step. In that cases the 
 castling should be distinguishable by appending a 'k', like
 already practized in promotion moves to make them unique.
 Overmore an engine should accept O-O or O-O-O (no zeroes),
 but only use them, when the GUI would demand for such a
 less precise notation.

Question on encoding Capablanca FEN strings:

Smirf actually encodes positions like:
rnbqckabnr/pppppppppp/0/0/0/0/PPPPPPPPPP/RNBQCKABNR w KQkq - 0 1

do you think it would be better to use completed numbers like:
rnbqckabnr/pppppppppp/10/10/10/10/PPPPPPPPPP/RNBQCKABNR w KQkq - 0 1

I am not sure, what to do. So I am gathering arguments.

Reinhard.

There is aready my proposal for Capablanca Random Chess. I repeat it here:

CAPABLANCA RANDOM CHESS (2004-Nov-26) Proposal 

This definition of CRC should cover the following goals:

a) creating an interesting drosophila for chess programmers 
b) using Capablancas 10x8 Chess board geometry 
c) using Capablancas piece set (incl. archbishop and chancellor) 
d) applying rules aligned to Fischer Random Chess 
e) avoiding conflicts to any claimed patents 

The CRC rules are: 

a) creating a starting position (one of 48.000): 
 1) the bishops have to be placed upon different colored
  squares; same rule applies to the implicite bishop pieces:
  queen and archbishop (aligned to FRC)
 2) the king always has to be placed somewhere between the 
  rooks to enable castlings (aligned to FRC)
 3) use only such positions without unprotected pawns (Chess)

b) describing a method of generating starting positions on 
   free squares by using a dice or random number generator: 
 1) select queen or the archbishop to be placed first (2x)
 2) place the selected 1st piece upon a bright square (5x)
 3) place the selected 2nd piece upon a dark square (5x)
 4) one bishop has to be placed upon a bright square (4x) 
 5) one bishop has to be placed upon a dark square (4x) 
 6) one chancellor has to be placed upon a free square (6x) 
 7) one knight has to be placed upon a free square (5x) 
 8) one knight has to be placed upon a free square (4x)/2 
 9) set the king upon the center of three free squares left
11) set the rooks upon the both last free squares left 
12) this establishes White's first row, the Black side 
    has to be built up symmetrically to this 
13) place ten pawns similar to traditional chess in a row 
14) skip this position if it has unprotected pawns or not
    at least three positions in line 1 differently filled
    compared to Gothic Chess (patented), this finally gives
    about 21.259 distinct starting arrays.
   
c) nature of (asymmetric Fischer-) castlings:
 1) castlings are (like in traditional chess) only valid
  if neither the affected king or rook has been moved, or
  there would be a need to jump over any third piece, or
  the king would be in chess somewhere from his starting
  position to his target field (both included). Therefore
  all squares between king and its target square (included) 
  have to be free from third pieces, same applies to the
  way the rook has to go to its target square.
 2) the alpha-castling (O-O-O, White's left side):
  like in FRC the king will be placed two rows distant
  from the border (here c-file) and the rook at the next 
  inner neighboured square.
 3) the omega-castling (O-O, White's right side):
  like in FRC the king will be placed one row distant
  from the border (here i-file) and the rook at the next 
  inner neighboured square.

d) performing castlings:
 within a GUI try to move the king upon the related rook
 or at least two squares into that direction; manually:
 1) move the king outside of the board
 2) move the rook to its end position (if need to)
 3) move the king to his end position

e) extended FEN encoding:
 1) the extended FRC-FEN could be used as a base
 2) 'a'/'A' are used to identify archbishops
 3) 'c'/'C' are used to identify chancellors
 4) '9' is used to mark nine empty squares
 5) '10' is used to encode ten empty squares
 6) if a castling enabled rook is not the most outer one
  at that side, the letter of his file has to be placed
  immediately following his castling marker symbol, where
  'q'/'Q' are used for the alpha-, 'k'/'K' for omega-side.
 
f) engine notation rules for castling moves:
 According to UCI convention the castling moves should be
 written by using both coordinates (source and target field)
 of the involved king. But there are castlings, where the 
 king does only one or none simple step. In that cases the 
 castling should be distinguishable by appending a 'k', like
 already practized in promotion moves to make them unique.
 Overmore an engine should accept O-O or O-O-O (no zeroes),
 but only use them, when the GUI would demand for such a
 less precise notation.

Why filter random positions based on Capablanca' extended board?

Let's talk first on FRC (I have written a small book on that in German language). One main intention to create FRC (or Chess960) has been to make it impossible to provide a complete opening theory for each position. Thus the number of 960 distinct starting positions is helpful to reach that goal. Uncovered pawns are not that problematic because any situation will have to be set up randomly very short before a game starts.

Looking at the Shogi game there are indeed three uncovered pawns in the beginning and the game still does exist today.

Capablanca's chess is somehow different to that because of the huge number of possible starting arrays viewing all shuffled combinations. But during the history from Carrera to Bird, Capablanca [through to contemporary versions] it has been a point of critic and missing acceptance of that extended board. So it could not be counter productive to select special starting arrays which seem to be positionally better constructed, without reducing the huge number of possible initial positions too much.

That leads to the both new rules: a) placing Queen and Archbishop (Archangel) at different colored squares, and b) avoiding unprotected pawns. I cannot see any negative payload connected with this two additional demands. More then 20.000 possibilities should be sufficient.

Also see a nice SMIRF (providing both: FRC and CRC) preview at: http://www.chessbox.de/_tmp/SmirfPrototyp.png

What is your goal, taa? Supposing you are intelligent I prosume you could
imagine that I notice that you are anonymously spreading desinformation
and nonsense here. Because the castlings like in Chess960 are not
symmetric, there is no redundance of mirrored positions. And CRC of course
is not trying to get as few as possible starting arrays, but instead to
filter positions, which eventually could be used as polemic arguments
against CRC, and to secure a more harmonic impression of that approach.

If you want to see a more European look of Shogi, see:
http://f51.parsimony.net/forum203932/messages/21.htm

The CAPABLANCA-RANDOM-CHESS idea goes back to early 2004. One of the first
publishings of that idea has been made by me at July 1st, 2004 in 

http://www.bauer-schweitzer.de/forum/index.html

To Greg Strong: of course you are right with your historical hints. There
might be some remarks to be added in the CRC description. The CRC text
should be extended, if there would be enough interested readers.

To Greg Strong and David Paulowich: indeed there are more traditional
names for C (Chancellor) and A (Archbishop). But those names do not
correspond to the pieces: nor to their gaits nor to their symbols. I have
tried to design more intuitive gait related symbols and noticed, that the
names would not be helpful for newcomers to the Capablanca extended piece
set. So I proposed names (partially already used differently in other
context) to enhance the readability of CRC board positions to interested
people. But that approach is only a suggestion, carefully keeping the same
initial letters e.g. to stay compatible within X-FEN.

To all posters here at CRC until now: thank you for your interest and
encouraging words!