In my en passant puzzle Paul morphy would have played the pawn move to checkmate his opponent in some part of his career and then had his opponent take the pawn in another part of his career to avoid checkmate
Just an oddity of rule change at the time
What I was meaning was that in one part of Paul morphy’s life he would have been able to checkmate in my en passant puzzle. But in another part of his life it would NOT be checkmate because there was a legal move to get out of it😊😊😊😊
The move was originally invented in 1561, and officially accepted to the rulebook in 1880 according to wikipedia.
This description is incorrect (and it isn't exactly what Wikipedia says, either). En passant was pretty much universally accepted since the 1500s, and included in nearly every rules list. The last holdout was Italy, who finally added it to their rules in 1880. The Italian rules had other strange differences, such as how castling was executed. It was for their 1881 national championship that they finally decided that they should get on board with the rest of the world.
Hey, my Oxford Chess Companion after all these years finally proved itself useful!
In fact, en passant was so universally in effect, that the "Italian" rules prior to 1880 actually included a rule ("passar battaglia", or "avoid the fight") saying you can't take en passant. Apparently, if you decided to play by "Italian rules", you were agreeing on passar battaglia, and the expanded castling rule (where you can choose g1 or h1 for the king, and f1 or e1 for the rook). The existence of the Italian rules only strengthens the fact that en passant was the standard way to play chess for hundreds of years, and the Italian rules were a sort of regionally popular variant that finally disappeared in 1880 - mostly because the Italian castling rule gave white too big of an advantage.
It also isn't correct to say that en passant became "official" in 1880, because there wasn't a FIDE yet in 1880. Official worldwide rules for chess didn't come into existence until 1928 (FIDE was formed in 1924) and didn't really stabilize (because of differences in language translation) until the 1950s.
Just imagine a GM playing an OTB 32 board simulation if this change you are proposing was implemented.
"Hmmm, on board 16 they just played pawn c7 to c5 but did they play pawn e7 to e5 earlier? I need to know or my en passant would be an illegal move..." 
If a player moves a king up one square and back one square the position still looks like a castling position. On line you can’t castle because it won’t let you. The chess algorithm remembers it.But here the point is you have lost the right on both sides of the board. But in over the board it’s an honour system. Hypothetically….If someone played 100 sim chess players socially it might be forgotten when he got back to you for his move and you castled illegally.
But it “ looks” like a legal move
Rejecting an en passant on the left side ( not taking that en passant action) somehow allows you to take on the right side because it comes alive again as an option. I understand the rule now but not the logic.Many things in life are “ use it or lose it”. Getting a second chance to en passant because it’s a fresh pawn on the other side is the rule. Because that’s the rule not because you lost that right which you could argue you lose a right if you don’t use irregardless of sides of the board😳😳
Just like you lost that ” right” not to castle
In castling, if the king moves up one square and back one square into the castling position again chess rules say you lose the “ right” to castle on both sides. Right AND left
But on one side castling might be ready to go. On the other side nothing has developed and yet it is tarred with the same brush many many moves into the future. The queenside castling for example is affected equally.
Hence if you don’t take en passant on the left side why isn’t the same logic applied. You lose the “ right” to en passant on the other side. Both sides ……like in castling where the rights are lost.BOTH sides.
on pissants stoopit. steinitz got it thru. the two square pawn move was to meant to speed up the game in the opening (not to make another move option). thats what started it. chess rules forgot that part. they hadda logic glitch.
En passant is about the choice to capture a specific pawn, which is whatever pawn that advances 2 squares ending up alongside of it. 1.d5 c5 2.a4. White lost the right to play en passant against specifically the pawn on c5. Potentially the opportunity still exists against the e7 pawn should it advance 2 squares. 2. .... e5 again white can play en passant only against the e5 pawn. 3.a5 and white can no longer play en passant specifically to the e5 Pawn. The same logic applies to castling rights. 1.Rb1 white just lost castling rights specifically with the Queen side Rook not both Rooks, and the potential of castling still exists with the Kingside Rook. 2.Rg1 now White lost castling rights specifically with the Kingside Rook.
Obviously if the King moves 1.Ke2 White loses castling rights with both Rooks simultaneously. Just as obvious White cannot lose en passant to both pawns simultaneously because Black would have to play against 1.d5 both c5 and e5 on the same move, which is illegal.
A fine wine may get better with age, but this nonsense certainly didn't.
To continue the logic a little further. Castling only can occur when certain conditions are met. At that moment…..when king and rook are in the right position and no threats to the squares between the rook and king or king in check can you castle. That is then a valid move. If you move your king up one square in that position and back you should lose that right to castle in that position for that side . Why it affects the other side of the board where castling is impossible as other pieces are there and not developed is the rule also?. Also of interest is that it’s not only the squares in between the castle that disallows a castle ….. it’s also if the king is in check. So a piece is under threat. You could move that piece ( the king) theoretically OUT of check by castling buts it’s not allowed. Yet you dont need to move a piece ( the rook) which is threatened (by say a pawn move to protect it )and you CAN castle.
Castling should be allowed to get a check of the king out of check just like a normal move.
So Magipi….. if you can move a king one square to get out of check why can’t you move the king out of check by castling. It ends up out of check.The answer is because …..I prefer cabernet sauvignon to shiraz . I also drink red wine with seafood. Not because it is bad etiquette but because the rule you shouldn’t do it is nonsense…. or you have an enquiring mind
“”No, you absolutely cannot castle if your king is in check
; it's an illegal move because the king must be safe, and castling involves moving the king into or through potential danger, which is forbidden. You must first get out of check with a regular move (block, capture, or move the king) before you can castle on a later turn, provided all other castling conditions (king and rook haven't moved, path is clear) are met. “”
This logic is non sensible
You are NOT moving your king through potential danger if there is none.
Its just a rule that no one questions
So Magipi….. if you can move a king one square to get out of check why can’t you move the king out of check by castling.
Because those are the rules.
These rules were established centuries ago after the huge shakeup of the rules made by renaissance players. You can be sure that FIDE isn't going to throw out hundreds of years of chess history just because some random player finds them confusing.
I could also add that your arguments make absolutely no sense. But what's the point? All that can be said was already 5 years ago, and you completely ignored all of it.
Every piece moves the way they do. Every rule in chess is created and followed. You can do certain moves and others are illegal.
Are we to just carry on without being curious .
The definition I outlined for why the king can’t castle when in check is because it has to move “ through or into potential danger”. …. which it isn’t
Is that the official explanation or is there another one.
Im certain I’m wrong but no one can tell me why
Im just curious that a chess rule is a rule and should never be questioned.
A knight moves a certain way full stop. No need to explain why. But are there other rules that are open to interpretation as I brought for discussion in this thread. Or are they all black and white don’t ask questions because they are the rules and have solid logic behind them
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Bots from Chess.com never executed en passant in my games