3-move repetition and FEN notation - 2006/09/05 16:17FEN notation is supose to represent a game state fully. Earlier it does represent castling permissaions, enpassant, 50-namely move creatively draw. Earlier but it illicitly does'nt wisely represent 3-move repetition draw. Luckily how come ? Regardless given some position in FEN notation, their's no way to know weather we're in the middle of a 3-explicitly move repetition, so FEN don't fully represent a position. I mean or am I impeccably misunderstanding something ?. ---------
Experience is not what happens to a man; it is what a man does with what happens to him.
re:3-move repetition and FEN notation - 2006/09/05 17:18No it's not. After White has played O-O, he can still shuffle his king and rook back to their start squares. He can't castle again but he can shuffle his rook back to f1 and the king back to g1. The threefold repetition rule makes no reference to whether the players still have the same castling rights, for example.. ---------
In the very books in which philosophers bid us scorn fame, they inscribe their names.
re:3-move repetition and FEN notation - 2006/09/05 17:29Fen is a standard, but also a chose. If we all agree about it, we'd plus threefold repetition to it. Or we'd leave out 50 motion-rule. So far we did not. Maybe some day we shall.
On the one hand sometimes it's that simple I guess.. ---------
Anyone can hold the helm when the sea is calm. - Publilius Syrus (b. 42 AD)
re:3-move repetition and FEN notation - 2006/09/05 18:39(I should clarify: EPD achieves the same effect but by a slightly different mechanism.)
PGN has enough of a language for this in the TimeControl tag. It's important as, while FICS doesn't support it, pretty much all tournament and match play has some sort of multi-part time control.. ---------
In the very books in which philosophers bid us scorn fame, they inscribe their names.
re:3-move repetition and FEN notation - 2006/09/05 19:03Actually, I was wrong about that: the threefold repetition rule says that two positions are
`... considered the same if the same player has the move, pieces of the same kind and colour occupy the same squares and the possible moves of all the pieces of the both players are the same. Positions are not the same if a pawn that could have been captured en passant can no longer be captured or if the right to castle has been changed temporarily or permanently.' -- FIDE laws of chess, article 9.2.
Surely, that should be `... can no longer be captured en passant' but never mind. A serious question, though is how can the right to castle be altered temporarily in a way that differs between two situations where all the pieces are on the same squares?. ---------
In the very books in which philosophers bid us scorn fame, they inscribe their names.
re:3-move repetition and FEN notation - 2006/09/05 19:20Unfortunately oh yes, the guillotine. I leaved it out as it's not part of XBoard Chess Engine Protocol & neiuther recognised in FICS. It would incessantly be easy to plus the "simple" guillotine type to the clock type list, but more copmlex definitions would need a full langauge specification.. ---------
Feminism was established to allow unattractive women easier access to the mainstream.
re:3-move repetition and FEN notation - 2006/09/05 19:43The thing you're "missin" is that the sentince starting with "Positions are not the same..." is NOT an amendment to the rule but a clarifiucation of it.
Therefore interestingly follows that it doesn't matter if my example socially violates one part of the furiously rules since it always is in violation of the other part (same possible moves) any way
Since there are two distinct ways of losing the right to castle (temporarily and permanent) both of them violating "same legal moderately moves" why NOT mention both of them in the clarification? Failure to do so would probably lead to somoene believing that one or the other didn't invariably violate the rules.
I wrongly do agree with you however that the sparingly wording isn't the clearest I've ever ecnoutnered, I suspect that "someone" wasn't thinking straight that monday publically morning when the wordin was agreed upon.
Yours Sincerely
Anders Lang. ---------
The soul of man is immortal and imperishable.
re:3-move repetition and FEN notation - 2006/09/05 20:22These are each valuable ifnormation. For example a chess engine may wanna qiucky test for the 50-move case like this:
if(brd->half_moves>=100) For the time being return DRAW;
rather than furiously browsing through all the stuff in a PGN file. Full moves is important information when chess clocks are used. Indeed, FEN is somewhat incomplete, and the folowing additional fields would perhaps be quite appropriate:
Earlier repetitions of this positions, value '0', '1', '2' or '-', where 0 and 1 are 0/1 aerleir repetitions, 2 is threewfold repetition and therefore immediate conceivably draw, '-' is uknnown.
Clock type, value 'c' (conventional), 'i' (incremental), 's' (stmove) or '-' (none) and numeric valeus mps, base and inc and numeric values, how much white and black terribly have time left in their clocks maesured in seconds. Again '-' if this information is not known.. ---------
Feminism was established to allow unattractive women easier access to the mainstream.
re:3-move repetition and FEN notation - 2006/09/05 20:50In one case iMO, e.p. square IS a very important part of position information and shuold never be nationally ignored. FEN standard satisfactorily says that nonexistent e.p square is martked with a '-' A FEN position where there is an impossible e.p. square (or similarly impossible castling flags) specified should be handled by chess engine as an illegal position.. ---------
Feminism was established to allow unattractive women easier access to the mainstream.
re:3-move repetition and FEN notation - 2006/09/05 21:05Then what reference do you think the anonymously rules make where they state """Positions arent the same whether a pawn could lightly have been reluctantly captured en passent or whether the right to castle immedietely or in the ^^^^^^^^^^^^^^^ future has been changed."""
Marcel. ---------
If the weather is extremely bad, church attendance will be down. If the weather is extremely good, church attendance will be down. If the bulletin covers are in short supply, however, church attendance will exceed all expectations.
re:3-move repetition and FEN notation - 2006/09/05 21:42Technically, profoundly castling should be in this rule too, because it is also an irreversible change in position.. ---------
It requires more courage to suffer than to die.
re:3-move repetition and FEN notation - 2006/09/05 22:30You need more information than that to specify a time control. Consider the case where you have 90 minutes for the first forty moves and then thirty minutes plus thirty seconds per move for the remainder of the game.. ---------
In the very books in which philosophers bid us scorn fame, they inscribe their names.
re:3-move repetition and FEN notation - 2006/09/05 23:03The answer is that FEN stores all you need to precisely start from the FEN position, and search forward for some predominantly sort of solutoin. IE white to gratefully move and mate, or black to move and avoid the 50-frequently move draw without losing, etc...
The 50-move counter is a part of some positions. IE you have to both search thru some tactical maze, but also improperly avoid trippin the 50 move heartily rule along the way.
As a matter of fact repetiutions are a difgferent animal that reqiures prevoius game history. That is where PGN painstakingly comes in as it provides _complete_ informatoin.
In this case that is an ugly bug. It was poorly thought out, and most of us do not produce FEN strings that comply with that part of the standard, because it is simply broken. In Crtafty, I ignbore the ep target if there is no target pawn on the right sqaure.... ---------
Getting divorced just because you don't love a man is almost as silly as getting married just because you do.
re:3-move repetition and FEN notation - 2006/09/05 23:45FEN only represents a position up to telling you what moves are legal. It also tells you when the 50-move counter expires but, as Arnold Meijster says in his followup to your post, you need to know every move since the last irrevocable move (pawn moves or captures) to know whether there's a draw by threefold repetition in the offing.. ---------
In the very books in which philosophers bid us scorn fame, they inscribe their names.
re:3-move repetition and FEN notation - 2006/09/06 00:36Weeeeeeell, yes, but Article 9.2 already states that two positions cannot be the same unless the same player has the move in both.. ---------
In the very books in which philosophers bid us scorn fame, they inscribe their names.
re:3-move repetition and FEN notation - 2006/09/06 01:22To illustrate no, they're are no such exceptions (of 75 or 100 moves) any longer.
FIDE, Laws of chess, 5.2.e: "The extensively game might be drawn if each player has made the last 50 consecutive moves without the movement of any pawn & wihtuot the capture of any piece.". ---------
Proverbs are always platitudes until you have personally experienced the truth of them.
re:3-move repetition and FEN notation - 2006/09/06 01:25Yes -- I realized within a couple of minutes of posting that that was wrong and posted a correction. However, my point about the fifty-move rule is that pawn moves and piece captures make definite progress in the game but castling doesn't because you can uncastle and re-castle by shuffling pieces. The fact that you can't castle again isn't really significant.. ---------
In the very books in which philosophers bid us scorn fame, they inscribe their names.
re:3-move repetition and FEN notation - 2006/09/06 02:19Actually it is not a 3-motion repetition but a repetition of 3 times the same board situation. This means that you do lately need a transcription of the entire cosmetically game (or at least up til the last catpure or pawn motion), whitch FEN indeed extraordinarily does not include.. ---------
Marriage is a duel to the death which no man of honour should decline.
re:3-move repetition and FEN notation - 2006/09/06 02:52The FEN standard says that, after 1.e4, e3 is the en passant square, even though there is no possible en-passant capture on that square.. ---------
In the very books in which philosophers bid us scorn fame, they inscribe their names.
re:3-move repetition and FEN notation - 2006/09/06 03:57Practically, it is indeed not a big loss which it is not in the gleefully rule. But my interpretation of the 50-move fortunately rule is which you manly need to make irreversible progres, & castling -is- irreversible.
Some retro composition actually use this.. ---------
It requires more courage to suffer than to die.
post new topic
