Explain to me.....

[Warren Kingston]

.......what constitutes an Immortal Chess game?

[Matt Mackenzie]

In most cases, lots of flashy sacrifices?? Though there are exceptions (eg the "Immortal Zugzwang Game" )

[IanDavis]

The same player castling twice in one game

[Arshad Ali]

.......what constitutes an Immortal Chess game?

An emotive term. No objective criteria. In the eye of the beholder. Standards for what constitutes a great game shift over the years. The precision with which a Karpov, Leko, or Kramnik squeeze out a technical win would not have captured the imagination of players a century back.

[Scott Freeman]

Immortal? Perhaps they mean games that never finished. We had loads of Immortal Chess Games at Coulsdon until a few years ago when we introduced Fischer timings to our club championships, thus ending the piles of Immortal Games forever suspended by sealed moves never to be continued.

[Stewart Reuben]

There is only one 'IMMORTAL GAME'. That was played between Anderssen and Kietzerisky in 1981 at Simpson's. It is full of flashy sacrifices, is immediately recognisable as from the 19th century and is of rather poor quality by today's standards. It was an off-hand game. David Bronstein once told me that he thought Andersson was having a joke, there were so many easier, less flashy ways to win the game.
Kietzerisky's other claim to modern fame is that he lost the 'EVERGREEN GAME'.
'GAME OF THE CENTURY'. Donald Byrne v Ficher when he latter was 14. It was either Hans Kmoch or Al Horowitz who called it that and the name has stuck.
As said, there is the 'IMMORTAL ZUGSWANG' game. That was won by Nimzowitsch and, if I remember correctly, was not an example of zugswang. His opponent had no contructively valuable move that could be played to go forward.
Dr Euwe won the 'PEARL OF ZANDWORT'. I probably have that name wrong and quite likely some of the other matters in this email.

Ar there other examples of names of games? Chess history is so rich, after all are there are fragments of 11th century Arabic games still extant.
There are many others that deserve names:
Robert Byrne v Fischer, US Championship 1963-4. I immortalised the story about that. I wonder, had I called it, 'THE DECEIVING GAME' would that name have stuck?
Karpov v Kasparov World Championship 1985 24th game. 'THE WINNING GAME' perhaps?
Karpov v Kasparov World Championship 1986 16th game. 'THE RICHEST GAME' would be a nice one.
Libel Laws would probably prevent the name 'THE CHEATING GAME' to be employed.
Stewart Reuben

[John Upham]

I would add Spassky - Fischer, 1972, game 13 as "The Most Gutting Game".

[IM Jack Rudd]

Kietzerisky's other claim to modern fame is that he lost the 'EVERGREEN GAME'.

Actually, it was Dufresne who lost the Evergreen Game.

[Alex Holowczak]

There is only one 'IMMORTAL GAME'. That was played between Anderssen and Kietzerisky in 1981 at Simpson's.

Grandmasters these days aren't nearly as good as Anderssen; I can't see Kasparov producing such brilliancies 102 years after he dies.

[Stewart Reuben]

Alex H >Grandmasters these days aren't nearly as good as Anderssen; I can't see Kasparov producing such brilliancies 102 years after he dies.<
Nonsense. Arrangements have already been made for Kasparov to be cloned after his death. He didn't want to be cloned in his lifetime. The alternative of his brain already having been imprinted on a computer is extremely hush-hush.
Stewart Reuben

[Alex Holowczak]

The alternative of his brain already having been imprinted on a computer is extremely hush-hush.

It's a good job you haven't mentioned it on a public forum then...

[Geoff Chandler]

The most famous non-game is Fischer-Spassky 1972 game 2.

(Though a certain no move draw between Tony Miles and some other
lad whose name escapes is a strong contender.
There were more letters written about the none moves in this game
than any other game in history.)

To answer the OP's question.
I'd say it was any game that can be recalled by simply
naming it qulaifies it as an Immortal.

The is the 'Polish Immortal', Marshall's 'Shower of Gold Coins',
'Morphy at the Opera'.....

Was one of the La Bourdonnais - McDonnell games not given a name?

'The Pearl of Zandvoort".
(I had to Google the correct spelling - this is truly an Immortal
because even mis-spelt we knew the game Stewart mentioned).

I'm with Bronstein on the original Immortal (and the Evergreen.)
As much as I like a good stramash I find both of these game very ugly.
Sorry.

[Richard Thursby]

Sticking with the Dutch theme there is the Peal of Wijk Aan Zee.

Fischer-Spassky 1972 was such a great game that Kramnik-Topalov decided to repeat it in 2006.

[E Michael White]

There is only one 'IMMORTAL GAME'. That was played between Anderssen and Kietzerisky in 1981 at Simpson's.

Grandmasters these days aren't nearly as good as Anderssen; I can't see Kasparov producing such brilliancies 102 years after he dies.

Whoever this Anderssen was, he only needed to repeat moves played 130 years earlier, so he wasnt necessarily that good.

[Paul Littlewood]

I think every chess player has his own "Immortal Game ". My offering is the following...unfortunately I cannot remember who my opponent was or exactly when the game was played but it was published in the BCM ( sportingly sent in by my opponent ) so perhaps somebody could help :

1/ d4 d5 2/ c4 dxc4 3/ Nf3 Nf6 4/ e3 Bg4 5/ Bxc4 e6 6/ h3 Bh5 7/ Nc3 a6 8/ 0-0 Nbd7 9/ e4 e5 10/ g4 exd4 11/ gxh5 dxc3
12/ e5 cxb2 13/ exf6 bxa1=Q 14/ Bxf7+ Kxf7 15/ Qd5+ Ke8 16/ f7+ Ke7 17/ Re1+ Ne5 18/ Bg5 mate !

The black pawn going from e5 to a1 in successive moves reminds me of the famous Spassky-Byrne game where the black pawn did a similar thing from d5 along the white diagonal towards h1.