user764: After watching a series of ChessBase India videos on YouTube, it is clear that GM's can easily remember 100s (possibly 1000's) of positions. Look at this one example by Vidit Gujrathi: https://www.youtube.com/watch?v=UebAM1CDxn8
My question: For amateurs, what are some good strategies to try to recognize a position and understand which opening it came from?

user9684: Simply you memorize just like everything else, repeat the opening positions.
The most common method to recognize the opening is by the pawn structure.  Since it's suggested that you only move a couple of pawns in the opening, although there are exceptions such as https://www.chessgames.com/perl/chessgame?gid=1282302, the opening can be reduced to a few openings based upon where the pawns are and which are exchanged.  

user14130: well, I should say there is a bit more discussion here to be made.
1- are you looking to memorize an opening line?
2- are you looking to recognize a position?
If you want to recognize more positions, you should study and spent more time on the game. the more you study chess, the better you understand patterns and can identify the famous positions.
for memorizing opening line, there is a two part to this.
1- for some positional opening, some general understanding of piece placement and pawn structures should be enough, with minimum lines to memorize, with high emphasize on general understanding and middle game forms. 
2- for more sharp opening, you should literally remember all the sharp lines, and one mistake could be fatal.
in this case, repetition and spaced repetition could be very helpful. maybe use chess base opening drill or chessable move trainer.
In short, dedicate more time to chess and study every single day, even if very small amount of time (15 min).

user20721: World champion Lasker said that he did not memorize anything that he could deduce for himself.
You need to know the BASIC tactical positions and mates but you do not need to memorize thousands of positions.  If you have seen the position and understand the motif then you will be able to do it in similar positions in your games. 
As to world champions and GMs they do not memorize the positions but they use pattern recognition to realise it is there then they can easily see the full combination to play. 

user19877: You really have a couple of questions here.
First, when it comes to memorization in chess, it has been shown that the more positions you have seen, the more likely you are to remember other positions. I remember once that GM  Susan Polgar was given some random chess positions, and she remembered the "normal" ones exceptionally well, however, when the positions were more random, she remembered at a rate that was roughly what anyone else remembered them.
There are books, unrelated to chess, that deal with learning to memorize better. I would love to see Master Simon Reinhard, World Memory Champion, write a book on memorizing specifically aimed at chess memorization.
Here are a couple more articles specifically on memorization that you might find interesting.

Memory Techniques: the Peg system (Part One)
Memory Techniques: the Peg system (Part Two)
Memory Techniques: the chess equation

Your second question, "what are some good strategies to try to recognize a position and understand which opening it came from?", is more about applying any memorization techniques to learning opening pawn structures, and the plans that are associated with them.
There are many books on this from the very basic, "Chess Opening Essentials: The Complete Series" by New In Chess to the classic "Pawn Structure Chess" by GM Andy Soltis to the more advanced, and outstanding, "Chess Structures: A Grandmaster Guide" by GM Mauricio Flores Rios.
These types of books teach you what you are aiming for in the opening, in general, and thus, when your opponent does not play "book" moves, you are not just lost with no idea what to do. You just have to read these types of books, and absorb some of the positions, and then you are back to the experiment with GM Polgar, even if not on the same level. You will begin to memorize, and recognize more.

764: <p>After watching a series of ChessBase India videos on YouTube, it is clear that GM's can easily remember 100s (possibly 1000's) of positions. Look at this one example by Vidit Gujrathi: <a href="https://www.youtube.com/watch?v=UebAM1CDxn8" rel="noreferrer">https://www.youtube.com/watch?v=UebAM1CDxn8</a></p>

<p>My question: For amateurs, what are some good strategies to try to recognize a position and understand which opening it came from?</p>
 9684: <p>Simply you memorize just like everything else, repeat the opening positions.</p>

<p>The most common method to recognize the opening is by the pawn structure.  Since it's suggested that you only move a couple of pawns in the opening, although there are exceptions such as <a href="https://www.chessgames.com/perl/chessgame?gid=1282302" rel="nofollow noreferrer">https://www.chessgames.com/perl/chessgame?gid=1282302</a>, the opening can be reduced to a few openings based upon where the pawns are and which are exchanged.  </p>
 14130: <p>well, I should say there is a bit more discussion here to be made.</p>

<p>1- are you looking to memorize an opening line?
2- are you looking to recognize a position?</p>

<p>If you want to recognize more positions, you should study and spent more time on the game. the more you study chess, the better you understand patterns and can identify the famous positions.</p>

<p>for memorizing opening line, there is a two part to this.
1- for some positional opening, some general understanding of piece placement and pawn structures should be enough, with minimum lines to memorize, with high emphasize on general understanding and middle game forms. </p>

<p>2- for more sharp opening, you should literally remember all the sharp lines, and one mistake could be fatal.
in this case, repetition and spaced repetition could be very helpful. maybe use chess base opening drill or chessable move trainer.</p>

<p>In short, dedicate more time to chess and study every single day, even if very small amount of time (15 min).</p>
 20721: <p>World champion Lasker said that he did not memorize anything that he could deduce for himself.</p>

<p>You need to know the BASIC tactical positions and mates but you do not need to memorize thousands of positions.  If you have seen the position and understand the motif then you will be able to do it in similar positions in your games. </p>

<p>As to world champions and GMs they do not memorize the positions but they use pattern recognition to realise it is there then they can easily see the full combination to play. </p>
 19877: <p>You really have a couple of questions here.</p>

<p>First, when it comes to memorization in chess, it has been shown that the more positions you have seen, the more likely you are to remember other positions. I remember once that GM  Susan Polgar was given some random chess positions, and she remembered the "normal" ones exceptionally well, however, when the positions were more random, she remembered at a rate that was roughly what anyone else remembered them.</p>

<p>There are books, unrelated to chess, that deal with learning to memorize better. I would love to see <a href="https://en.chessbase.com/post/how-to-keep-things-in-your-mind-an-interview-with-world-memory-champion-simon-reinhard" rel="nofollow noreferrer">Master Simon Reinhard, World Memory Champion</a>, write a book on memorizing specifically aimed at chess memorization.</p>

<p>Here are a couple more articles specifically on memorization that you might find interesting.</p>

<ol>
<li><p><a href="https://en.chessbase.com/post/memory-techniques-the-peg-system-part-one" rel="nofollow noreferrer">Memory Techniques: the Peg system (Part One)</a></p></li>
<li><p><a href="https://en.chessbase.com/post/memory-techniques-the-peg-system-part-two" rel="nofollow noreferrer">Memory Techniques: the Peg system (Part Two)</a></p></li>
<li><p><a href="https://en.chessbase.com/post/memory-techniques-the-chess-equation" rel="nofollow noreferrer">Memory Techniques: the chess equation</a></p></li>
</ol>

<p>Your second question, "what are some good strategies to try to recognize a position and understand which opening it came from?", is more about applying any memorization techniques to learning opening pawn structures, and the plans that are associated with them.</p>

<p>There are many books on this from the very basic, <a href="https://rads.stackoverflow.com/amzn/click/com/9056913409" rel="nofollow noreferrer" rel="nofollow noreferrer">"Chess Opening Essentials: The Complete Series" by New In Chess</a> to the classic "<a href="https://rads.stackoverflow.com/amzn/click/com/1849940703" rel="nofollow noreferrer" rel="nofollow noreferrer">Pawn Structure Chess" by GM Andy Soltis</a> to the more advanced, and outstanding, <a href="https://rads.stackoverflow.com/amzn/click/com/1784830003" rel="nofollow noreferrer" rel="nofollow noreferrer">"Chess Structures: A Grandmaster Guide" by GM Mauricio Flores Rios</a>.</p>

<p>These types of books teach you what you are aiming for in the opening, in general, and thus, when your opponent does not play "book" moves, you are not just lost with no idea what to do. You just have to read these types of books, and absorb some of the positions, and then you are back to the experiment with GM Polgar, even if not on the same level. You will begin to memorize, and recognize more.</p>
