Grandmaster's abilities

The ability to calculate ahead is not the main difference between GMs and untitled players. Not even close.
Reti was asked how many moves he usually looked ahead and replied "As a rule, not a single one".

Hi,it is true.They can also play blindfold on different chess boards. But 20 moves ahead with all variations is pretty impossible also for an engine unless there are a lot of forcing lines.Variations,secundary variations,subvariations,20 moves is a bit too much.If you mean 20 moves in one or two main variations then answer is yes,else it is no.

Forcing moves they probably can. I think I remember reading the opening pages of Soltis How to think like a Grandmaster (I never bought it, as I was just looking) and he suggested that the seeing more 7 moves ahead was unusually brilliant.
I'm also sure in the intro to the Art of Checkmate they show an example of an 11 move king walk and say no one could possibly expect to see all the moves leading to 'mate, GM's included, but there was certain principals and intuition involved.
Even at that, I remember hearing that Botvinnick played this brilliant defensive move against Tal at which point Tal offered a draw. After the match Tal had nothing but praise for him, saying he must have seen this crazy long 15-20 move variation and Tal couldn't believe it. Botvinnick said he'd seen nothing of the sort, having nearly no clue where the game was going in 2 or 3 moves but he'd simply applied a principal of chess.

Two days ago I won an otb Blitz tournament cup with 15/16, only two draws against rel. decent oppositon. I talked to a team-mate of mine how little I calculcated at all. It is really amazing how far you can get with almost no calculating. No fishing for compliments, rather scary.

Two days ago I won an otb Blitz tournament cup with 15/16, only two draws against rel. decent oppositon. I talked to a team-mate of mine how little I calculcated at all. It is really amazing how far you can get with almost no calculating. No fishing for compliments, rather scary.
Agreed!!
So this is interesting-and re the question begged by @blueemu's answer-is it the application of basic principles plus intuition linked to experience for the best move ,that will generally lead to the best outcome,at least for GM's,rather than a carefully worked-out visualized plan? Is this what computer engine algorithms do,as opposed to comparing all possible options for so many moves ahead and then picking the optimum line?

Two days ago I won an otb Blitz tournament cup with 15/16, only two draws against rel. decent oppositon. I talked to a team-mate of mine how little I calculcated at all. It is really amazing how far you can get with almost no calculating. No fishing for compliments, rather scary.
Depends on how much positions you know in your memory!
If someone knows 10^43 positions, like 32 men TB, he can move 100% correctly and tell the outcome 100% correctly with 0 calculation.
If you know 40 million positions , like LC0(Leela chess zero) and alpha zero, you can play like 2200 strength with 0 calculation.
(In one research, a GM knows, 200,000 positions in his brain).

https://clips.twitch.tv/PuzzledDaintyGnatMikeHogu
Yes. They can. But it all depends on the position complexity.

Its all about experience.If you see the blitz(even bullet) games of Hikaru you will realize his intuition is very well developed since he is familiar with most of the positions and patterns that come up in his games.
To answer your question,If its a forced variation grandmasters can calculate till as many moves they want but in unforced positions they rely on their knowledge and memory.
So this is interesting-and re the question begged by @blueemu's answer-is it the application of basic principles plus intuition linked to experience for the best move ,that will generally lead to the best outcome,at least for GM's,rather than a carefully worked-out visualized plan?
The problem with such classroomish heaps of verbiage is that you can't use them to come up with good moves. So what good are they really?

People play blindfold chess, so they can visualize 100 or 200 or 300 moves ahead.
But this says nothing about the quality of moves visualized.
Visualization is nothing. Rendering correct evaluations after calculating short sequences is everything.
So this is interesting-and re the question begged by @blueemu's answer-is it the application of basic principles plus intuition linked to experience for the best move ,that will generally lead to the best outcome,at least for GM's,rather than a carefully worked-out visualized plan?
The problem with such classroomish heaps of verbiage is that you can't use them to come up with good moves. So what good are they really?

'People play blindfold chess, so they can visualize 100 or 200 or 300 moves ahead."
If anyone has ever posted a more asinine comment, I'll be a monkeys' uncle.
If you can SEE one move ahead, after accurate evaluation, you can become a Master. Simple as that.

'People play blindfold chess, so they can visualize 100 or 200 or 300 moves ahead."
If anyone has ever posted a more asinine comment, I'll be a monkeys' uncle.
If you can SEE one move ahead, after accurate evaluation, you can become a Master. Simple as that.
The key word is "visualize"
Laymen use words like calculation, visualization, and analysis interchangeably, so I can see how my post might confuse you (or the OP).
But if all we're talking about is visualization then the only limit on a GM is time. If they wouldn't get sick or age or etc then they could visualize infinite moves ahead.
As a simple example, I can have a beginner visualize 16 moves ahead.
Don't believe me? Try it yourself.
1.a3 a6
2.b3 b6
3.c3 c6
4.d3 d6
5.e3 e6
6.f3 f6
7.g3 g6
8.h3 h6
9.a4 a5
10.b4 b5
11.c4 c5
12.d4 d5
13.e4 e5
14.f4 f5
15.g4 g5
16.h4 h5
See. Easy.
As I said before, it's the quality that counts. Calculating short sequences and rendering an accurate evaluation. That's what chess is about, even for engines (although "short" for them is longer than for us )

You seem to be the one with your snoot in the air. And hikaru... said--in rather elegant fashion--precisely nothing. Which was precisely my point about such specious airy effusions.
You have high standards for this stuff, as usual.
But it's usually just a beginner asking about something basic. Sure the explanations aren't perfect (my posts included) but it's the basic ideas that are important.
For example he (more or less) asked whether a GM finds good moves through pure calculation.
The answer is no, and it's also true that they use their experience. Sure it's something of a word salad after that but with that the OP learns a little bit (like chess isn't pure calculation).