Hi
today i had a case where a rook was pinned to the king and protecting an attacking queen at the same time. I couldn't capture the queen with my king because theoreticaly (and obviously practicaly) she was protected by the pinned rook. But theoretically and practically its impossible to move the rook. how should we treat this? The engine decided that the protection caused by the rook was active, but in fact practically it is not. should this be considered by engines or by the rules?
Okay, so I think you're saying that a pinned rook protected an attacked queen, and your king could not capture the attacking queen, even though the protecting rook was pinned.
Chess rules say that a king can't move into check, so if the king captures the queen, it would be in check by the rook. So, the rook is protecting the queen anyways.
Yes, that was my point. But i can see no logical contradiction if we would say, that the check caused by the pinned rook is first active when the king is moved and the pin lifted. Kind of "indirect" check. because i think that in every other case a pined piece is treaten as a dead piece, why not in this case too? Well, at least in our minds. For an engine the threats from a pinned piece are active. I find this "ambiguity" interessting. You know, why should a check be an exception?
It is also interessting that a pinned piece can never cause checkmate because it can always be captured by the pinning piece.
There are two kind of pins: offensive and defensive. an offensive pin is when a piece is jumping between the king and his threat, causing eo ipso a "NEW" threat, f.e. protecting his own and attacking the enemy king at the same time. Then there is the passive pin where the king is hiding behind his own pieces, which can never declare chess, since the only possible way to do so would be the enemy king to step in, which is not allowed.
I found this by trying to create a board setting where an offensive pin should checkmate. But no matter how many such pins may happen, they will never checkmate. Even if a pin causing a pin causing a pin, which is causing a check can not win the game, since all offensive pins can be neutralisied.
So here is this very general truth about chess: checkmate can only be caused by unpinned pieces! :D
Ok, see it that way: the first „captured“ King loses. Game over.
Your proposal leads to complications: What, if the pinning piece is pinned itself? What if the piece, that pins the pinning piece, is pinned?
Thankfully, the chess rules are clear about check and pinning. You can avoid a check by:
- taking the attacking piece
- moving the king to an unattacked field
- putting a piece in the line of the attack.
Pinning the attacking piece is not a valid defense against a check.
@AlphaZeroAII "So here is this very general truth about chess: checkmate can only be caused by unpinned pieces! :D"
Example without double check:
lichess.org/study/eGZPuKrm/SmUVfZvI#0 Things would be a lot simpler if a king had to be captured in order for the game to be won, e.g. in
@ProfDrHack 's example, after Qe3, Bxe3 (because otherwise the queen would capture the king), then Bxe1 and white loses because their king hes been captured, and Bxb6 is irrelevant. Does anyone know where the rule came from (that a king cannot be captured, only placed in a position such that capture would be unavoidable next move)?
@mCoombes314 : "Things would be a lot simpler if a king had to be captured in order for the game to be won"
According to
@ProfDrHack's example the king will be captured next move, hence the criteria for checkmate has been fulfilled. As
@Sarg0n states the first to capture the king wins the game. In order to checkmate there has to be a check. In the above example the king is in check, i.e. will be captured next move. This threat HAS to be dealt with. If the king cannot escape capture being captured then it is done, all over; set the pieces up for the next game as there cannot be another move. Remember the move order goes white, black, white, black until the game is over and someone cannot make a move. In the above example white cannot move so black cannot make another move. Is this not simple enough or am I missing the point?
