Studying openings is highly UNDERrated!

For good inexpensive wines, check out the Aussies or the Chilean wines. 

When Bent Larsen was asked how many games he had in his database, he replied that he had about 60,000. When asked why he had so few, he said that's all he could remember! 

The 100,000 positions claim makes sense even before you read the article. After reading the article, it makes even more sense.

How many lines do you think an actor can memorize? I know actors who have memorized all of Shakespeare's greatest plays. Hamlet alone has more than 100,000 words.

The article is not about rote learning. It's about a measure of knowledge. So the answer of IM pfren about the number of beers drunken while studying is more serious than the first glance tells.

This is a good analogy actually to demonstrate that learning openings isn't just about memorising sequences of moves, but understanding them. Nobody would imagine that actors learn plays by rote without knowing anything about them.

I have literally never seen anyone recommending memorizing things without understanding them. 100% of the time the issue is brought up, everyone agrees that you should understand the openings and their move choices conceptually.

"Charness (20) used books on chess openings ( more specifically the five book series Encylopedia of Chess Openings (21) to establish the number of opening moves experts know - a kind of declarative knowledge."

Does anyone see problems with the above?

@PossibleOatmeal, I've never heard anyone recommend dumb memorisation, but I've seen a lot of people DO it...

Yes, you cherry-picked a quote and took it out of context. The quote comes in the middle of a discussion of what others have done. Here's the rest of the quote regarding Charness' work:

Charness [20] used books on chess opening (more specifically, the five-book series Encyclopedia of Chess openings [21]) to estimate the number of opening moves that experts know – a kind of declarative knowledge. Assuming that players know three or four systems with both white and black, he concluded that grandmasters know about 1,200 distinct opening sequences. Charness also discussed the knowledge that players have about middle games and endgames, although quantitative estimates turned out to be elusive. [Emphasis added]

Ponz is sneaky that way .  

The people at chesspub forum have memorized more than 100,000 opening moves, which is great. The bad thing is that the big majority of them are rated well below 2000... 

That's a gratuitous attack on a place where chess authors and chess readers come together to discuss openings, books, articles, and general chess information. I don't know if "the big majority" are well under 2000, but it seems to me that is not true at all. I'd estimate that about half are +2000 strength. Most of the rest are interested in serious improvement. There are also a few trolls there. You should know this since you have been active there too.

Nope. Life is short and many commenters are obtuse -- to put it charitably -- or mischievous. (Have you ever been rick-rolled?)

Plus I see the onus is on the writer to communicate to the reader, not an obligation for the reader to figure out what the writer is up to, no matter how lazy or incompetent or thoughtless he may be.

1. grandmasters are not experts.

2. How is opening sequences defined?  For example when the chess opening books mentioned gives a sequence and say a game to 50 moves--is the total game part of the opening sequence?

3. Theory changes, Theory changes quickly. Those 5 books are very outdated now and can no longer be regarded current opening theory.

4. When a master is studying opening theory it goes something like this:

Ponz, why didn't you just apologize for misrepresenting Charness' work?

Charness published his analysis in 1991. The authors used this as background information. They also quoted from De Groot (1965). They also did their own research, with real, active OTB masters. 

It's fine to disagree with academic journals, but please read the article critcally first. Find out what their methodology, their assumptions, and their data say first.

While Bobby Fischer was preparing for Spassky in 1972 he memorized, by intention or just in the course of study, all 800 or so of Spassky's published games.

At 40 moves per game and 80 color moves per game, Fischer memorized 64,000 moves just for one match.

I have no problem believing that masters have memorized 100,000 opening moves.

I suspect most class players know more moves than they realize, though if you asked them  to write down all those moves they might not come up with much -- like that trick where you are asked to write down the names of all fifty states and you can only get to 45.

Masters, for the most part do not memorize all the opening moves in some 5 volumne book on the openings.  They may memorize some basic sequences which lead to ideas and then understand the ideas.

Opening theory changes. From day to day.  When I  started studying the Ponziani I could see the opening theory played for many decades was out of date and theoretically not sound. There are books printed today on the Ponziani which give page after page of losing theoretical sequences which per the book are "theory"

Look at the Sicilian Defense. Nobody can memorize all the opening sequences of just that one opening. 

Assuming players know 3 or 4 systems of openings is very ambigous. What does it mean? Does it mean they know the systems out of a book?  Or does it mean they know the systems out of several books?  What is defined as an opening?  What is a system of an opening? The Ruy Lopez is an opening and very few masters know every single response to every single move they will recieve. Instead they rely on their own chess knowledge when playing after the first few moves. Yes, there are some sequences which last 20 moves but these are not necessarily the best moves. 

Also, how are the moves counted--to get to 100,000 moves for an expert or master?  Do they count duplicate moves as in my previous examples.

There are so many unanswered questions because the terms are not defined. 

Once again ponz, please read the article first. Then you may realize that some of the unanswered questions were actually answered.

When I started my first USCF tourament I had very little opening knowledge. Maybe  50 or so moves for all the openings combined.

Still, I did ok. 

 If you are a master, it is necessary to memorize maybe 5000 to 10,000  moves, knowing the ideas behind the moves is much more important.

You certainly do not need to memorize 100,000 moves. Not to just be a master.  In one of the last tournaments I played in the opening I played vs a GM, I had only memorized to the 6th move in the game and did ok.

I will reread it as I did not read the whole thing with all the subnotes.

But, I did not see some of the definitions I was looking for.

ponz: I'm with Smyslov on this. Read the article. Think a bit more about it.

The claim is that masters have 100,000 opening moves memorized -- that's an average and it's not a requirement for being a master.

Reshevsky had a terrible memory for openings, but he could still reinvent the wheel over the board and function as a grandmaster.