Well, if a piece is pinned it's illegal to move it.

Rule 3.9.2: No piece can be moved that will either expose the king of the same colour to check or leave that king in check.

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TheOtherHobbes 3 hours ago | parent | next [-]

Unlike en-passant and castling, pinning and discovered checks are consequences of lower-level rules.

At the "Is this move legal?" level, they don't need unique rules of its own if the lower-level rules are specified correctly.

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JohnKemeny 3 hours ago | parent [-]

3.9.2: no piece can be moved if that exposes or leaves its own king in check.

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333c 2 hours ago | parent [-]

That's a consequence of not being allowed to put yourself in check (by any means).

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anamexis an hour ago | parent [-]

The only way to put yourself in check is by moving.

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yifanl 32 minutes ago | parent | next [-]

The only action you can ever take in chess is moving.

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333c 39 minutes ago | parent | prev [-]

Did you mean putting your opponent in check? In chess, you are not allowed to put yourself in check.

	▲	anamexis 22 minutes ago \| parent [-]
		You said “ That's a consequence of not being allowed to put yourself in check (by any means).” My point is that there are no other means.

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gobdovan 3 hours ago | parent | prev | next [-]

You can also pin a pawn to a queen, but the pawn can still legally move.

	▲	HiroProtagonist 2 hours ago \| parent [-]
		You're both right, depending on whether you mean relative pin vs absolute pin.

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munchler 2 hours ago | parent | prev | next [-]

The point is that, logically, the first part of that rule (“expose the king”) is implied by the second part (“leave that king”), so the first part is redundant. You could simplify the rule to:

No piece can be moved that will leave the king of the same color in check.

	▲	emil-lp an hour ago \| parent [-]
		You should submit it to FIDE.

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saberience an hour ago | parent | prev [-]

Pinning isn’t a rule, it’s just something that arises from other rules.

Also, pinning can happen with pieces that don’t include a king, which means you can just move out of the pin and expose whatever other piece.

It’s just a chess tactic, not a rule. It’s like saying a chess skewer is a rule too.