It's not like Chess is some weird, esoteric game where there is a gray area of whether or not moves are legal or not.
Maybe I'm biased. I'm currently working on a toy chess engine myself.
K R r
_ _ _
k _ _
Then you also get people who don't know about rules regarding castling through check, etc.
Basically what I'm getting at is, there are moves that even people who casually play chess might misunderstand, so OP was implying that they were not one of these people.
If one thinks about chess as if the goal were to capture the opponent's king before one's own king is captured, this makes perfect sense. But sometimes the concept of checkmate muddles peoples' intuitions.
Edit: Thanks for the clarifications. lowercase = one color, uppercase = other color. K = king, R = rook
The question is... does the rook R still provide attack/check even though it is pinned by rook r to King K?
The answer is yes.
His situation is correct, however I don't think any experienced chess player would not know that.
It's a common mistake that is likely to be made in finals from beginners.
Actually it is exactly like that.
If you play tournament chess, like USCF tournaments, then there's no doubt what the rules are. However if you play casual chess, like with some random guy in the park, then be prepared for some misunderstandings.
Some things casual players think are rules:
Pawns move two squares only on the first move of the *game* not the first move of the pawn
You can't promote a pawn the move after it arrives on the 7th rank, you have to wait a move
Perpetual check is illegal (somewhat like the Ko rule in go)
Capturing En Passant is generally not known
As far as I know, these rules are extremely standardized in most or all areas of the world where chess is known. I have heard about some special rules for competitions that can differ, like timing limitations and end-game rules. I'm also aware of many variations of chess, but those are always clearly discussed as variants.
Can you elaborate on this? I've never seen any claim to this effect, only that a pawn on its starting rank has the option of moving two squares (but cannot use that to jump over or capture a piece) (e.g. as stated http://en.wikipedia.org/wiki/Pawn_(chess)). Are these different claims or am I misunderstanding?
> You can't promote a pawn the move after it arrives on the 7th rank, you have to wait a move
Same here. "The new piece replaces the pawn on the same square, as part of the same move" (e.g. http://en.wikipedia.org/wiki/Promotion_(chess))
I'm only showing wikipedia cites to indicate that if these are wrong they are widely spread, and hoping that you have better cites.
I actually did not know this one, and I thought I played enough Chess to know all the rules.
When I played tournaments in high school, most players knew about it, but most players were still quite amateur, so one could offer up a position in which the opponent could perform an en passant, but the en passant was actually fairly detrimental, and more often than not the opponent will take it, because "hey cool I can do that weird pawn move".