How can you deliver checkmate with a king?

So the rock itself moved? Unless somebody pushed it we have a much bigger problem.

ONLY THE EYEBROW MOVED...

Dear god, there was no death laser. THAT was what killed the man.

WAIT!! the rock had lazer eyes!! oooooooooo

i was initially referring to a regular old stone kind of rock. just a boulder that casually moved out of the way of the laser. That's why i was concerned.

O. well you misunderstood. They were totally talking about DWAYNE THE ROCK JOHNSON.

I think legally the rock would be an accessory. The rock assists, but does not actually take part in the act of what the laser does. So in most of these chess diagrams the king would be an accessory, it certainly assists the final position, but does not take part in the actual checkmate.

yes. An accessory to murder....hehe

you shouldn't use a rock in chess. You don't get the points advantage for getting other pieces with a rock, you just end up breaking the pieces and having to spend like $30 dollars to replace em'

You've got to do a discovered checkmate

So, before Mad Max completely takes over, the resume of what we know and do not know for sure:

We know for sure, in the above position:

1. That the player checkmates his opponent by playing the king to e7. It's in the rules
2. That the move Ke8-e7 checkmates the opponent. It's in the rules.
3. That Ke8-e7 is a King's move - probably not by any rule but by every dictionary.
4. The Rook checks the opposing King after the move Ke8-e7 is played. It's in the rules
5. The opponent's king is checkmated after the move Ke8-e7. It's in the rules.

What we do not know for sure is that:

1. You can say that the King checkmates or delivers checkmate (to) the opponent.
2. You can say that the Rook checkmates the opponent after the King's move. 

I think though it is very hard to deny "1" of the unsures when you add up "2" and "3" of the sures. It is how we deduct conclusions from two premises (a syllogism).

It is however possible that "2" of the unsures is considered true as well - mainly because it refers to a different phase of the game - i.e. after the checkmating move is played. Notice that "1" of the unsures obviously starts from before the execution of the checkmate move.

Finally, even if one would agree to the Rook checkmating the king ("2" of the unsures), still makes it unlikely that "1" would then suddenly be untrue. After all, they clearly describe different points in time. So they could both be true - one as an action, the other one as a state. Not that I think you would find an official anywhere that would support "2" but it does not lead to a contradiction.

We know for sure the rook checkmates the opponent after the king moves because of 4. The rook checks the opposing king after the move Ke8-e7 is played. It's in the rules.

The checking piece is the one that checkmates because it's the one that is attacking. Attacking the opposing kings square is required for checkmate. The king move does not attack the enemy king square, so it is not the checkmating piece. It's in the rules.

That is a sentence stuck in your mind but nowhere in the rules, unlike the facts that the player checkmates and the king's move checkmates. For both are citations in the rules but not for the rook checkmating after the move and neither for the king checkmating after the move. But at least the language rules back up the conclusion that the king executes the checkmate move - without making a claim on the king's role after the move. The word "when" in relation to a rook attacking a king means no more than that the attack may be simultaneous with the checkmate state - which is self-evident when describing a state. A state only defines a frozen moment in time with all the different states of all the individual places, objects and potentials in it. It is a snapshot, a photograph. Language that describes things in the same photograph (like a pawn and a king) obviously need not refer to the same things unless expressly stated by the rules.

"A player’s king is checkmated when the square it occupies is attacked by one or more of the opponent’s pieces and 
the player has no move that escapes such attack. "

That is the rule. A piece must be attacking he enemy kings square for the enemy to be checkmated. A king cannot attack an enemy kings square. But a rook can.

The language in the rules does not specify HOW the rook came to be the checkmating piece. It does not say if it was promoted, it does not say if it moved there, it does not say if it was a discovered check. Only that a piece (in this case a rook) attacks the enemy kings square.

If there is a belief the king is the checkmating piece, why do the rules only mention the attacking piece and the enemy king? Why do the rules exclude the option of other pieces checkmating?

That describes a king that is in checkmate, not a piece that checkmates.

The rules exclude the option of other pieces checkmating because it's not their job to settle arguments like these. Their job is to teach people how to play. The rules don't care about grammar, or the definitions of words.

We are beyond belief on most points. The rules say that the (opposing) king is checkmated by the (last) move. When we know that the last move is a king move, it follows that the king checkmated the opposing king. The rules also say that the player checkmates his opponent's king. So there is apparently room for nominating more than one deliverer of the checkmate state. That is why it is worth investigating other candidates like the rook attacking the king.

Nobody denies that a piece must attack the opposing king in the checkmate. And nobody has ever denied that. And of course the rook attacks the king here in the checkmate position. That is enough to identify it as the king attacking piece - but not as the checkmating piece.

The critical word in the definition of checkmate is AND. Attacking the king is not enough - that is check - but there are other conditions to be met to turn the check into checkmate. Nothing in the rules suggests that you should favor the checking piece over other participants in the checkmate state. On the contrary - considering that we already have three checkmate producers covered by the rules in the (last) move - It is not clear why we would need to add a fourth one with a different profile. Good enough to say that the king is checkmated after delivery has already taken place.

The HOW matters because the HOW is always about "following the rules". The checkmating move must be legal (FIDE article 5.1.1). The evaluation of the checkmate position also matters - it must be really checkmate. So both matter. What matters least is how we name what is going on. Except in the categories I isolated in an earlier post and which are mainly about communication!

Oh but it DOES describe a piece that checkmates. It's right there in black and white "when the square it occupies is ATTACKED by one or more of the opponents PIECES".

So it actually DOES describe the piece that checkmates. A checkmate must be an attack. The rook (in our examples anyway) attacks the enemy kings square. Everyone agrees that's the checking piece. The king does not attack that square. In the rules only two types of pieces are mentioned, the one(s) that attack the enemy king, and the enemy king. That's it. NO mention of how the piece came to be the attacking or checkmating piece. No mention of discovery, no mention of promotion, no mention of moving that piece, etc.

So why do you suppose that is? If the piece that moved is so important to define a checkmate, why not say that in the rules?

I guess I didn't see that part in the rules. You say a king checkmates an opposing king. That is literally impossible. A checkmate, as we all know, is an attack on the enemy kings square. It's against the rules for a king to attack the enemy kings square. It would put both kings in check simultaneously, so that move is not allowed under the rules of chess.

Since the move happens (lets say a discovered check) and then checkmate occurs I can see where we could nominate more than one piece for deliverer of checkmate. That could make sense. It's not unlike the scenario before about the accessory to murder (in this case checkmate).

The king would be an accessory. He does not carry out the actual checkmate, but he assists. He is an accessory (or accomplice depending on where you live). He gets out of the way so the checkmate can take place. So imagine this a legal scenario. In this diagram is the king the accessory or the principal? In other words, which one is actually attacking (checking) the enemy king?

Stacking up fiction. It (USCF, not FIDE) says WHEN and it says AND and that makes all the difference. You can "open the package" and check if the content is OK after it has been delivered. Nobody cares whether it was delivered by train or by plane (the title of my next CD) in terms of the result.

Whatever other pieces could be mentioned, refer only to the state of checkmate, not the delivery. The other participating pieces are the ones necessary to make sure the king cannot escape. You have a fixation on the idea that there has to be a checkmate delivering piece in the checkmate position while there is none. The checkmate is a result of the total position as is clear from the WHEN .... AND ... sentence.

And yes, the piece that moved is that relevant - just as the plane is that relevant in getting the package on your desk. Btw, open at your own risk (the Transporter).

That's all well and good, but it doesn't answer the question. I wouldn't necessarily call the rules of chess "fiction", but to each his own. Again, in that diagram, is the king the accessory or the principal? They are different pieces, they serve different functions, even in this diagram they perform different tasks, so we cannot say they are equal (or both principals). So which one is the principal?