IRONCLAD PROOF THAT LUCK AFFECTS SOME CHESS GAME RESULTS

This is NOT about game-changing blunders. Blunders reflect skill (or its absence), not luck. There are other situations, however, where "luck" is the best way to describe events on the board that decided a game's outcome. 
The full argument is developed here: https://www.facebook.com/share/p/17yemeosi4 Give it a read and let us know what you think.
FM Jon Jacobs

Rxd6 sure looks like a win. But I'm not certain.
I would say that blunders reflecting skill or lack of skill do not exclude luck.
The fact of the nature of something doesn't mean that something else has to be excluded. Sometimes it does.
If luck is defined as the opposite of skill and its also insisted they can't co-exist in the same context - well with such defining one could 'have' any reasoning one wants.

Yeah I think when luck is debated among serious chess players the parties tend to make the assumptions you mentioned -- that for purposes of such discussion "luck" and "skill" signify mutually exclusive influences. 
As I noted at the beginning of my post, subject those assumptions, chess people usually conclude that blunders reflect skill alone, and that only skill can determine results (except for trivial cases where the deciding factor is wholly external to the players' move choices -- such as a power outage or natural disaster, or a medical emergency afflicting a player mid-game).
My counter-argument is that a decisive continuation both players overlooked -- meaning, the ultimate winner went into a situation where he would have been busted if not for a saving resource he hadn't seen at the time he committed himself to that position -- represents an outcome that turned on luck.

If that's the case, then I've been lucky more times than I care to admit. Not just in chess, either.

Jon - that's a very good point - or rather excellent point that you're making.
And yes - chessplayers tend to make the assumptions you mention.
And we seem to agree that they're invalid assumptions.
Your counter-argument is crushing. And represents reality.

In the diagram it appears that after Rxd8ch although white has a move in hand how can he rescue his knight from the looming Rb2 by black ?
Well he could try Nc5 and after the continuing b6xc5 and white's b4xc5 ...
then white has a very nasty protected passed pawn at c5.
Can black survive that? I would think not but again not certain.
Point: black will have to tie himself in knots containing that passed c-pawn while white's rook goes after black's vulnerable a- pawn ...

no luck no duck. no rubber duck for you my friend.

what

I would chew it. I love latex.

im kidding if that wasn't obvious.

Bro you're treating me like a toddler

ta ta

Opto is usually wrong.
So often he begins with an invalid premise or worse.
He'll try to shut down conversation with he 'already' did something.
But usually fails.
He did nothing to refute Jon's argument.

Opto is usually right

So we disagree. That's fine.
Just now he tried to argue that since good players play to increase the chance the opponent will make an error that he must be right.
It doesn't follow.
That's like saying that since 2+2 =4 then 3+3=2
Opto proved nothing. He always claims false victory too.
Nobody has to buy.

"That's like saying that since 2+2 =4 then 3+3=2
Opto proved nothing. He always claims false victory too.
Nobody has to buy."

Now you're making things up

What did I make up?
Nothing.
Nobody has to buy.
But you can.
Its especially the kids who often cave in to Opto.
But you're already better than him. .
You can admit that you're wrong. You have in the past.
Now - did Jon want these exchanges in his forum?
Maybe not.
But Opto proved nothing.
Because Jon the opening poster never claimed that good players don't play to increase the chance of the other player making an error.
Opto went after a strawman.
There. Opto's disinformation interfered with.
Efficiently.

And sure, good players play to increase the chance the opponent will err. That approach probably was always in wide use at high levels, but I have the sense it's become far more recognized and widespread in the past 15 years or so (= THE CARLSEN ERA), largely due to its association with Carlsen's playing style. (And based on the earlier discussion, inducing the opponent to err, and the opponent actually erring, is 100% SKILL not luck... so Capa's maxim about good players being lucky is irrelevant for purposes of this discussion.)

That approach also ties in with an evolution in how engines are used in opening prep. Top GMs in their prep no longer aim to find novelties that confer some objective advantage. Rather the aim is to find novelties that take opponents out of their own prep and lead to positions that are playable and more comfortable psychologically/stylistically (not necessarily objectively better) for the player who introduced the novelty than for their opponent.