How can you deliver checkmate with a king?

That's a good point about the "check". I think it's pretty clear the pawn in this example does not check the king, it moves out of the way so the bishop can check the king. The rules of chess say that a "check" is when one or more pieces attacks the enemy king. so the bishop would be checking, not the pawn. So it seems like it would be the bishop (that is checking) that would be the deliverer of checkmate. The pawn isn't checking, isn't attacking, and isn't checkmating.

For a double checkmate it seems like both pieces would be delivering the checkmate simultaneously. And for a stalemate, which pieces delivers it? I don't know. I suppose it could be any piece that prevents the opponent from moving. It's not an attack, but a more passive position so I don't know if I would even use the word deliver.

It just seems like the very words "check" "checkmate" and "deliver' kind of prevent a king from delivering a checkmate. Just like in my example the pawn is not delivering checkmate.

Gotta be extra sure the red king doesn't escape!

To get the "Killer King" achievement, you need to move the king in such a way that it will be checkmate, and 1 way to do that is to do a discovered check.

Well apart from 0-0 and 0-0-0. In the examples given they look a bit like discovered checks - a piece getting "out of the way" - but there are also puzzle ends where the castling king participates in the checkmate by taking a flight square from its opponent (here g2):

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The words "check" and "checkmates" have verb and noun expression in our language. As nouns they express states - black's king is in check, black is checkmated - as verbs they refer to the last action taken to bring about the state. This reflects how we often look at team competitions. Last weekend Europe beat the USA for the Ryder Cup. The matchwinner was Fleetwood who took the decisive point for Europe. He was the deliverer of the win even though his point was in no way better or different from the other european points but his action took them over the winning line. In football the winning action could be a 0-2 defeat in the group phase of a WC - sufficient to proceed on goal difference. In itself the winning action need not be a special achievement as long as it attains the higher goal by virtue of all team contributions. In chess, the higher goal is checkmate, not check, a pawn promotion or a queen capture. And that is how the modest pawn defeats the looming black king simply by getting out of the way.

As said, the case for check is debatable but the bad news is that the debate is already overtaken by reality. Or perhaps we should say it's 50-50. Yes, the king is in check by the bishop (noun, state), but the pawn move checked the king (verb, action).

looool

But that's not what the rules of chess say. And it's not what the dictionary says. The rules of chess say the bishop is checking the king, not the pawn. Because the bishop is attacking the king, not the pawn. Therefore only the bishop can be checkmating, not the pawn.

The dictionary says, under the verb check "to put (a chess king) in check". It lists checkmate as both a noun and a verb. But the rules of chess make it pretty clear only the attacking piece can check, or checkmate. The piece that moves out of the way cannot do that (unless it's a double checkmate).

I think the reason is because the last action is the bishop checking the king, the pawn moving is the second to last action. I agree the pawn exposing the bishop creates a state of checkmate, but ONLY because of the action taken by the bishop. The action, the deliver, of checkmate. If the bishop was not checkmating the king, then the game would go on. It wouldn't be the end.

So I have a question for you. And I'm basing it on the rules of chess. In the example I gave of a discovered checkmate, is the pawn attacking the king? I know it was the last recorded move, I know it exposes the king to checkmate, but is the pawn itself attacking (threatening to take) the king?

Yes, the rules would say or imply that the bishop is "checking the king", not the pawn. And that is what I say as well. But "checking the king" in the checkmate context is a state, not an action. In itself "the state of check" is a potential to make a capture of the king on the next move (if allowed) but a potential is not an action. The action is a visible change on the board.

The chess rules do not really resolve the issue since the past is irrelevant for deciding whether or not a position is "checkmate". That's why it just defines "the state of checkmate" However, game players and puzzle freaks have a need to describe "causation" of checkmate and have assigned identity to the unit causing the checkmate. Which in itself is a simplification since, on a higher level, it is "black" or "white" delivering the checkmate or, even higher, player A or B. So you can say "lfPatriotGames checkmated Carlsen" or "white checkmated black" or "pawn David checkmated king Goliath" all of which are associated with the action of checkmating.

I'm not sure what puzzle freaks have to do with anything, but ok.

I don't think there is any need or reason for the rules of chess to specify the action of checkmating. We have a dictionary to define words. Those words are then used by organizations like the USCF and FIDE.

In my example, where the last move was a pawn exposing the checkmating bishop, both the rules of chess and the dictionary say the piece that attacks (checks) is the piece that checkmates. No mention is ever made of the piece that simply gets out the way. Which makes sense, because the pawn is not attacking, is not checking, and is nowhere near the king.

Only the piece that checks can checkmate. Therefore, only the piece that checks, and checkmates, can DELIVER the checkmate. In my opinion, the opinion of puzzle solvers does not override that of the USCF, FIDE, and the definitions used in current dictionaries.

All you write is imaginary. None of those organizations use your interpretation on the delivery of checkmate. Remember how this thread begun with the "killer king" which is not only the correct assignment for checkmate delivery but also the one that has been viewed by countless receivers and witnesses of the same title. I doubt anyone objected so you are in a universe all of your own. As I explained, the field of puzzles - which has an organization of its own, the WFCC (allied to and coordinating with FIDE) - has much more use for terms which hardly play any role in games but are essential in the formulation of challenges and the analysis of piece functions.

In the actual FIDE laws the delivery of checkmate (the action) is exclusively attributed to the players (as in the last paragraph of my previous post) which is quite OK.

The glossary definition of the state of checkmate does not refer to its causation:

checkmate: 1.2. Where the king is attacked and cannot parry the threat. In notation ++ or #

Note that the definition is wrong because it suggests that the king must parry the threat while it is actually the player - simply because the player also has control over the other pieces which can parry the threat, Nevertheless, it is correct in the sense that it relates checkmate to the options in the future and not the past. There is zero reference to how the checkmate position came about other than (in other paragraphs) that players caused it.

The bottom line is that you do not understand the mathematics involved. Chess is an abstract game built on a mathematical model. The primary elements in that model are objects, attributes and actions. Checkmate is an attribute. Of what? Not of a piece, moving or otherwise. It is an attribute of a complete chess position and you will find it in a relational table for chess positions which couples chess units to squares on a chessboard. Changes in states occur upon executing moves - also known as production rules. Once you got these things under your belt you will come to see that one need not distinguish the definitions of delivery on any of the states - be it check, checkmate, stalemate, dead or technical draw. If you need 5 definitions to define delivery in these 5 cases, you are doing something wrong. More importantly, you don't need any definition of delivery for any of the states when you play chess. They are only required when you do "puzzling" or "participate in social fun by means of killer king awards".

Repeating where I started: You are wrong. It's not a matter of opinion but of mathematical modelling rephrased in the imperfect environment of human languages.

you have to move the king out of the way, so there is a checkmate with two castles for example

or with a castle and a queen, that's how it works easiest I'd say

yeah that's how it works I think, the king can squeeze between the two rooks and you got your checkmate :-)

but this one won't work I think, because as you move your king up, the other king can follow still being protected by the opponents king

I did not suggest to move the king up but to castle! It counts as a king's move and it checkmates.

I'm not so sure it's me that's wrong, as the dictionary is wrong in this case. I'm just going by the definition of the words check, checkmate, and deliver. Also, the USCF and FIDE describe conditions of check and checkmate (but not deliver). Your concern is with them, not me. I didn't write the definitions, I didn't make the rules of chess.

I have no doubt chess.com considers the killer king award an award based on moving the king. But that's not the question. The question is can a king deliver a checkmate. The answer is no. They can help, they can facilitate, but no, they cannot attack or deliver a check or checkmate on an opposing king. That is against the rules. Based on the definition of the words FIDE uses, only the attacking piece can perform (deliver) checkmate. The piece that moves out of the way (whether it's a pawn, king, or any other piece) isn't the attacking piece. So there is no possible way they could check, or checkmate. Thus no way they could deliver the checkmate.

Indeed, FIDE stops at assigning delivery to the players - more than 10 times in the FIDE laws : "the player checkmates" - and since I live in the world, not in the USA, I don't care much what USCF says. I do care what the WFCC (World Federation of Chess Composition) says because it is the place where language and conventions make numerous extensions to the standard chess rules which have no need for concepts such as "delivery". There is not a single composer or solver who does not know how delivery of checkmate or check or stalemate or anything is defined because it is essential knowledge in the creation and solution of compositions. I'll look it up one day in the Composition Codex though everyone may find it too obvious to waste a definition on

And indeed, the Composition Codex delivers many extensions on chess rules for puzzle solvers and people posting diagrams in general. The conventions that you may castle (unless disprovable) and not play e.p. (except when provable) and that you cannot randomly claim a draw on the basis of some possible but unprovable 50-move series - all come straight from the Codex. Just to show that the composition conventions often step in where the chess rules leave holes.

In the final analysis, the frailty of your reasoning comes from assigning a huge significance to the tiny "check" part of "checkmate". Which is purely incidental. Had the rulemakers decided not to hand out an exemption for stalemate positions then your story would have been ridiculous while the one referring to the last action would still stand! And it stands as a generic principle for the delivery of all other states like "check" and the various draw terminations.

It sounds like you are trying to say only the player can "deliver" check or checkmate, and not the pieces on the board. If that's the case then the answer is still no. A king cannot deliver checkmate.

But if it were the pieces on the board, the answer would definitely be no. As the king may not attack (check) another king. Either way, the answer is no.

Causation is often assigned to a chain of participants transferring command to the next one in line. Like the politician orders the general who orders the captain who orders the sergeant who orders the soldier to fire his gun. All play their part in delivering the shot and all may be considered deliverer on their level of authority. When you just look at the board you'll see a piece delivering the checkmate but when you look at the game you see the player moving the chess unit doing the dirty work.

The reason that the bishop is not in that chain is that it does not shoot the king (it is not allowed just as "passing" is not allowed) and it does not transfer an order in any way. Even if the rules would permit the players to continue after checkmate (as probably was the case in some distant past) then you might only assign the "king killer" role to the bishop after the opponent had played a move that kept the king under its attack of the bishop. Commonly a checkmated king has a choice of ways to die.

Yes, I agree all play a part. The opposing king plays a part, the pawn plays a part, the bishop plays a part. They all play a part. All the pieces cover a flight square or otherwise prevent the opponents king from moving. But one, and only one, piece delivers the checkmate.

The other pieces help, and play a part. The pawn moves out of the way, but it does not "deliver" a checkmate, since it's not attacking, checking, or threatening the king in any way. So whether we want to say only the players deliver checkmate (and not the pieces) or we want to say the pieces deliver checkmate, either way, a king cannot do it. A king cannot check or checkmate another king. It's against the rules of chess.