great question @A_0123456 , thanks for asking, made me think and learn a bit.
@nayf is one of the few remaining who directly equates IQ with an artificial online chess rating.Basically,that's what they do when they got nuthin'.Just keep trailing me around,laddy..yr sure to pick up lots of useful stuff to help you thru life.
Well, as a guy who is working on a knightrider engine, I found this thread useful. I hadn't considered the possibility of a triple check, and a triple check via en passant would be a good test case to help weed out bugs.
In atomic chess, it would be possible with an explosion blowing up 3 pieces in front of the king and letting 2 bishops and a rook check.
Now the question would be, "Is it possible to quadra-check ?"
Now the question would be, "Is it possible to quadra-check ?"
The real challenge is the fabled "octa- check".
@nayf said (#10):
> I agree that for a proven moron with a 1200 rating, a question that forces one to think is not great at all.
You are right, of course. Still, the "don't feed the trolls"-rule applies here.
Otherwise, i would point out in reply to #12 that an artificial online rating might not be proof of (the absence of any measurable) IQ but the inability to understand basic mathematical truths (like shown here: lichess.org/forum/team-philosophical-philosophers/0-divided-by-0?page=3 ) probably is. But, of course, i will not do that.
krasnaya
> I agree that for a proven moron with a 1200 rating, a question that forces one to think is not great at all.
You are right, of course. Still, the "don't feed the trolls"-rule applies here.
Otherwise, i would point out in reply to #12 that an artificial online rating might not be proof of (the absence of any measurable) IQ but the inability to understand basic mathematical truths (like shown here: lichess.org/forum/team-philosophical-philosophers/0-divided-by-0?page=3 ) probably is. But, of course, i will not do that.
krasnaya
@krasnaya
Yes, when I said "proven moron", I meant from numerous other threads, where he proved incapable of following an argument, as in the link you provided. His low rating isn't the proof, just an expected confirmation. The imbecile even thinks I'm "trailing [him] around", when he replied to me first. But you're right that one ought to refrain from feeding the troll; additionally, as has been remarked, one can't fix stupid.
To summarise the answer (from #7), all pieces except a N attack in a straight line (diagonal or vertical/horizontal). Straight lines intersect at most only once. So two non-N pieces cannot simultaneously be blocked by a single square and attack the same second square. This holds for any two non-N pieces. So no N move or pawn move, whether en passant or not, can unblock and thus discover a double check. So they cannot themselves add a third check, only a second check.
Yes, when I said "proven moron", I meant from numerous other threads, where he proved incapable of following an argument, as in the link you provided. His low rating isn't the proof, just an expected confirmation. The imbecile even thinks I'm "trailing [him] around", when he replied to me first. But you're right that one ought to refrain from feeding the troll; additionally, as has been remarked, one can't fix stupid.
To summarise the answer (from #7), all pieces except a N attack in a straight line (diagonal or vertical/horizontal). Straight lines intersect at most only once. So two non-N pieces cannot simultaneously be blocked by a single square and attack the same second square. This holds for any two non-N pieces. So no N move or pawn move, whether en passant or not, can unblock and thus discover a double check. So they cannot themselves add a third check, only a second check.
IQ is overrated, I would say that the state of the mind and character traits (leadership qualities, charisma, likeable personality) are much more important than high IQ. Some sociopaths (those that do not end up in a prison cell) also tend to excel in life, there seems to be many examples as of late.
I'm sorry if i'm not clear, I don't really master english language.
A long time ago, the chess rules said something like :
The player must move to avoid the checks when his king is checked by one or two pieces.
Somebody found a position where the king was in check by two pieces, then a piece moves that allows the king to be checked three times and the checkmates the other king. (Sorry, I don't have the reference).
Since then, rules have changed, and the king must escape all the checks (that is not limited by two).
A long time ago, the chess rules said something like :
The player must move to avoid the checks when his king is checked by one or two pieces.
Somebody found a position where the king was in check by two pieces, then a piece moves that allows the king to be checked three times and the checkmates the other king. (Sorry, I don't have the reference).
Since then, rules have changed, and the king must escape all the checks (that is not limited by two).
In my proof on the previous page (#8), I missed a slight point.
What is important is to focus on the squares that change state during a move. In any move except en passant (which I covered) two squares are affected. One of them goes from occupied to empty, and the other goes from either empty or containing an enemy piece to containing a friendly piece.
Thus, as I showed, the square that becomes empty can only result in the creation of one check, because of the move geometry of chess pieces.
However, the other square can only result in one check (the one from the friendly piece that ends up there) because for no chess piece does a friendly piece in the way restrict its motion less than an enemy piece or an empty square in the same location would. In simpler terms, there is no piece that can hop over friendly pieces but not enemy pieces on the same square.
If such a piece existed, a triple check could result from a capture where the capturing piece was blocking a square, and the captured piece was blocking a square but the capturing piece landing in the same square does not.
In standard chess, there are no such pieces, so there can be no triple check.
EDIT:
At one point, I need the assumption that not only do pieces that make repeated steps in one direction and are obstructed by obstacles make steps of constant size, but also that any two pieces that make repeated steps in this manner in the same geometric direction make steps of the same size (in chess that is one unit orthogonally or square root of two units diagonally).
Does anyone see where that comes in? And does anyone see how you could set up a triple check in a variant where this is not the case?
What is important is to focus on the squares that change state during a move. In any move except en passant (which I covered) two squares are affected. One of them goes from occupied to empty, and the other goes from either empty or containing an enemy piece to containing a friendly piece.
Thus, as I showed, the square that becomes empty can only result in the creation of one check, because of the move geometry of chess pieces.
However, the other square can only result in one check (the one from the friendly piece that ends up there) because for no chess piece does a friendly piece in the way restrict its motion less than an enemy piece or an empty square in the same location would. In simpler terms, there is no piece that can hop over friendly pieces but not enemy pieces on the same square.
If such a piece existed, a triple check could result from a capture where the capturing piece was blocking a square, and the captured piece was blocking a square but the capturing piece landing in the same square does not.
In standard chess, there are no such pieces, so there can be no triple check.
EDIT:
At one point, I need the assumption that not only do pieces that make repeated steps in one direction and are obstructed by obstacles make steps of constant size, but also that any two pieces that make repeated steps in this manner in the same geometric direction make steps of the same size (in chess that is one unit orthogonally or square root of two units diagonally).
Does anyone see where that comes in? And does anyone see how you could set up a triple check in a variant where this is not the case?
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