Bernhard, do we really need to memorize? why?

[ShiroKuro]

When I first started playing (6 years ago, as an adult) I occasionally played  pieces from memory in recitals, but at some point my pieces got longer and my sight-reading got better, and I got out of the habit of memorizing. Or I should say, until then I had memorized without planning to, naturally, and as memorizing became more difficult because of the pieces, and less necessary because of my comfort with score, I stopped doing it.

Now, reading Bernhard's advice, and Chang's, about how to memorize (and of course always hearing my teacher wonder when I'm going to memorize something) I am slowly trying to incorporate memorizing into my routine.

But I can't help but wonder if I really need to memorize. After careful attention to what I'm doing when I play with the score, I have concluded that after the earliest stages of playing something, I am not sight-reading note-for-note, but looking at the score as a whole, as a memory guide sort of.  There are parts that I look at specifically (kind of like how you might look at the keyboard for a big jump) but in generally I'm just sort of following the grand staff with my eyes (again, not the same as sight-reading or the way we read something for the first time)

People say there are several types of memory, and one is visual. Well, looking at the keyboard is one way to use visual memory, why is it bad to look at the score as another way?

Also, recently I've been trying to keep adding to my repertoire, and I also want to play a selection of Christmas songs every year, so being able to always go back to the score has really helped me. Being always comfortable following the score seems to make it much easier for me to have a playable repertoire as well as keep working on new pieces. (And of course, at the end of Nov every year, I don't have to re-memorize those carols, I just re-read them, which I find much easier)

So my first question is: why memorize if I don't feel like I'm hindered by having to have the score open?

The second question is: Is it possible to take a piece I've played for years, but only with the score, and memorize it now? It seems to me that that is more difficult than memorizing it in the earliest stage of playing it.

Bernhard, I hope you have a minute to give your advice and comments, because I have been putting most of your other suggestions to use, with great results.

[nicko124]

I will add in a very quick contribution before Bernhard steps in with a long thread. Obviously you don't need to memorize every piece of music that you learn but for highly advanced long pieces can you imagine how much of a joke it would be to play in a concert atomosphere with a page turner.
Somebody like Hamelin would never do this.

I am not sure if this is the right understanding of the matter, after i learn a piece of music the score is their for me to check that i haven't memorized it incorretly.

You also mentioned Christmas pieces, whether they need memorizing when you can site read them easily. I have often wondered about this point as well, at the moment i do not think that it would hurt to memorize them as chang states 'you don't need the book every time you want to play it'. However i always have a section of my music where i would rather keep them as sightreading so my skills are kept constant in this department.

Again i am not sure if what i have said is all correct but that is currently what seems logical to me. If i have made errors than i expect a more experienced pianist to corrrect me in this thread.

[quasimodo]

Even though you don't aim at public performance, one reason I can see for memorizing is that reading the score is going to consume an important part of your attention which would be much better used in focuing on the musicality of your playing.

[nicko124]

Even though you don't aim at public performance, one reason I can see for memorizing is that reading the score is going to consume an important part of your attention which would be much better used in focuing on the musicality of your playing.

Yes. Good Point. So you mean that if the piece is memorized and part of your subconscious than you can focus more on the emotion of the performance - - loud and soft sections etc.


ShiroKuru: Can you really imagine playing a piece such as Liszt - Un Sospiro looking at the score, seroiously noone i know would see any use in doing that.

[redhead]

I am also very interested in this.  I read Chang's section on it, and the sentiments seem to be echoed here.  You need to memorize because its expected in performance to perform from memory. 

But for a non-professional, this isn't a compelling reason to do it.

Now, I'll memorize some sections especially if they have lots of large leaps since looking for the large leap and watching the music is tough.  But in general, with something like a Bach 3 part invention I don't feel any additional freedom from memorizing.

[kilini]

I am procrastinating memorization. So, here's a question: is it possible to truly memorize a piece I've learned or sighread a million times or memorized by finger memory? Chang said I'd best start with a piece never played before.

[marialice]

I am procrastinating memorization. So, here's a question: is it possible to truly memorize a piece I've learned or sighread a million times or memorized by finger memory? Chang said I'd best start with a piece never played before.

It is possible. But Chang is right, it's a lot easier to start with a piece never played before. Then the line between what you know and what you don't know yet is a lot clearer, not blurred by "what you think you know".

I am not a professional and I probably will never be one. Yet I tend to memorize the pieces I work on seriously. Not because I should or because I want to play without the score, but because it makes me play better. I have to know a piece back to front, and weak spots come out much clearer when playing from memory. When I have memorised a piece, I feel a lot more confidence and freedom.

[IanT]

Somebody like Hamelin would never do this.

But Richter, Myra Hess and Bela Bartok did it all the time!

Ian

[Tash]

i prefer memorising my pieces, i hate looking at the music, so that's a good enough reason for me! i find it lets me focus less on each individual note and more on the piece as a whole. i don't likve being reliant on the sheet music- it allows me to forget cos i know i have the option to do so if it's staring right in front of me

[ted]

I do not perform at all but memorise everything I play. I guess it is personal opinion but I don't feel I really grasp something musically unless I have it all in my head. If it's all there I can also use it to influence my creative work on the spot, as it were. The only times I use music are firstly to learn a piece and secondly to refer back to if I am unsure of a detail, which event happens less as I get older. As might be expected, I am a poor sight reader, but in my case it doesn't matter very much.

[rebel1ns]

personally i dont try to memorize, as i play the piece over and over again the memorization naturally comes...

[Daevren]

I have a video with hamelin performing with sheet music/page turner.

Is this really a problem for people? To memorise a piece? To me it seems easy. But then again I don't have a huge number of pieces in my head.

[ShiroKuro]

I was wondering if this subject had just been discussed to death, but all the responses say otherwise, thanks for all the comments everyone!

Regarding performing with the music, I don't think we can really make any sweeping statements about that, sometimes you see pianists play with the score on the stand, sometimes you don't. And I personally learned how to turn pages without stopping so that I can do longer pieces, but I have also had my teacher turn for me before (though I prefer doing it myself)

The question is, am I really limited by not being able to do away with the score?

I don't believe that having the score open means that the piece isn't all in my head.  Remember the distinction between "sight-reading" and "playing with the score." When I play a piece in my repertoire that I've been playing for 3 years, with the score, I am definitely not sight-reading.

Regarding having something in our heads, we have the keyboard in our heads, but we still want to look at it from time to time. And I have a very visual memory of the scores I use, I can visualize where certain passages are (i.e. the top of page 2, the middle of page 4 etc) As I said, I am not looking at the score note for note, but on phrases as a whole, or sections, passages of the piece.

Marialice said being able to play without the score makes her play better. I guess this is what I want to know, how does it make it better?  Because I just don't feel hindered by having the score (and since I don't feel that it's a problem, I'm not motivated to make the effort to truly memorize!)  But maybe I'm missing something and it is a problem.

Quasimodo said:
"Even though you don't aim at public performance, one reason I can see for memorizing is that reading the score is going to consume an important part of your attention which would be much better used in focuing on the musicality of your playing."

This is another thing I don't get. The musicality is in the score. This is not to say that I don't add anything to the score, but that the score, by its very nature, is musical. Whether you're interpreting (adding musicality) to a piece that you memorized or that you're looking at from the score, I don't get the difference.

Nicko124 said:
"Can you really imagine playing a piece such as Liszt - Un Sospiro looking at the score, seroiously noone i know would see any use in doing that."

Why? That is not so different from any other piece... How about something really fast, either you have the score out or you don't, but you're not sight-reading, so Nicko, I don't see your point. Obviously, yes, there is a lot on a score of that level, if we're just talking about Liszt,  the scores of La Campanella or the "little bird" one (sorry, can't remeber the title in English!  Legendes S. 175-1) are equally "full."  But if you can get that music into your head and into your fingers, surely you can also follow it on the score. It's not a question of whether there's any use in playing it with the score.

The question is, how is one limited by having the score out, or is it conceivable that one is actually not limited by having the score out and at a certain point, is it just personal preference?

I don't mean it to sound like I'm defending playing with the score, I'm just trying to really understand the benefits of memorizing....

[robert]

I am just adding a few things to the debate.

Of course, as I hope all of you understand, it is not a matter of memorising or not memorising. The first time to look at the score, you begin to memorise using your theory knowledge. The first time you play a part of the piece, you memorise more of it but you use other memory functions as well as muscle memory, musical memory and keyboard memory. The second time you try it, some parts are already memorised while you perhaps struggle with some difficult fingering settings. When you can more or less play the entire piece without too many mistakes, you have already memorised 90-95% of it and only use the sheet as support to make sure you do not forget a certain passage, the dynamics etc. Here is where all normal human brains get lazy as the goal is more or less achieved. The human brain never "overlearns" anything but just enough to achieve a certain goal.

But what is the goal? For sure it must be to be able to perform it really well? In this phase, make a recording of the piece and you will likely notice that it is not as well as you feel it is when you play yourself. For the majority of people, you need to memorise it entierly to be able to play it really well and here is where you must make a very important thing. Change the goal! Convince the brain that the goal is NOT achieved yet! The goal can be to play it perfect, without a single mistake and perhaps even be able to play it perfect like 3-6 times in a row! Also, have some checkpoints from where you always can restart the piece. That is a very good safty mechanism.
When I performed live which is many years ago, I often practised this way. I tried to play the piece perhaps 4 times in a row without a single mistake. If I failed the last time in the last bar, I had to restart the whole session. A pain of work but you are rock solid on the stage and feel very confident which also makes you perform it a lot better musically...and I have never brought a sheet up on the stage ever.

If your goal is just to study the piece for use of theory, the above does not apply.

And one very important thing (which I hope most of you know already).
Once you have learnt it by heart (and I mean learnt it with everything it involves), never ever bring the sheets to the stage on the actual performance. The reason is that you will during these circumstances (when you are nervous, playing on another piano/grand, people around are not quiet) begin to doubt your memory and read the sheet...and you will most likely screw up.

[nicko124]

Shirokuro: What i meant about Un Sospiro was that you are playing a complicated fast piece with a page turner who will distract you (constantly changing pages mostly out of perfect time). You have to focus on what your playing as well as looking at the notes including the the crossover notes and playing them. If you look at the music for a piece like Un Sospiro it will make looking at your hands difficult to fit in as well. Unless the piece is imprinted on your memory (which is what we are discussing not to do but rather read the notes) you will have to play without looking at your hands and this could quite easily lead to errors.

On top of all this you have to focus on putting the emotion in the piece.

I am not trying to say that you can't do this, i would be very impressed if you could in a concert situation. I am however saying that it is a lot to deal with on top of the fact that you might be nervous as well.

Than again if the sheet music would eliminate the nervous factor for you than that is one less thing to deal with on your mind.
Choose the best method for you in terms of performance and how you prefer to play it.

But for me personally my eyes would not be quick enough to scan through all of Un Sospiro and play it, the page turns would also be distracting as well.

[Egghead]

Hi, an aspect I remember from Chang and find very true myself is that once you have learnt a piece by heart you can truly practice it - whenever and wherever you go, as well as any part of the piece you feel like. Also, at your whim, you can compare bits from different sections. You can compare different pieces. This may sound just like a practical reason. I also agree with Ted:
 

I do not perform at all but memorise everything I play. I guess it is personal opinion but I don't feel I really grasp something musically unless I have it all in my head. If it's all there I can also use it to influence my creative work on the spot, as it were.

It means you have the music in you.

One more reason: I find memorization a challenge. It is truly satisfying when accomplished.
Egghead

[ShiroKuro]

Nicko, of course Un Sospiro is a complex piece-- and I can't play it, so it's a bit hypocritical of me to go on like this!    but just because a piece is long, doesn't mean you need to have page-turning. I went to the concert of a Russian pianist... her name is totally gone from my head at this point! Her first name starts with an "I" I think and her last name with an "S"  (that is pathetic!!! no wonder I don't memorize!!       Anyway, she used the score for each piece she played, but each piece was on a rather large board, no page turning at all. I wanted to have a look, but couldn't!  And at the end, for the encore, she came back with a book of Chopin pieces and played from the book, as if she hadn't prepared one specifically! (I am sure she had choosen them, but she didn't have her scores prepared the same way as the pieces in the program)  Anyway, that 's just one example.

All the point everyone has made are very good, but I still don't feel like my questions have been answered... Or maybe I should say, I'm still not convinced.

Bernhard, are you going to join us?

[Egghead]

no wonder I don't memorize!!       All the point everyone has made are very good, but I still don't feel like my questions have been answered... Or maybe I should say, I'm still not convinced.

Bernhard, are you going to join us?

hahaha. maybe starting by memorizing music will help you in life generally 

here comes my Bernhard-impersonation (either I happen to be right, or THIS should prompt him to post  ): Do what is right for you, but arrive at your decision by testing. Choose two pieces of similar difficulty. Learn one the usual way. Memorize the other as recommended by Chang (i.e. early on). See which you play better, with more enjoyment, with more understanding/interpretation, right away, and after leaving the pieces for a couple of months. Tell us what you find 

5 links about memorization and 2 about connections to martial arts (katas?).

End of impersonation.
maybe a question to ponder: who else memorizes and why, who doesnt, and why not? (e.g.  orchestral players, violin soloists, conductors, guitarists, ...)
Any views?

[mound]

My sight reading isn't very good, so I tend to memorize naturally anyway.

For me though it comes down to only two reasons why I would prefer to memorize:

1. I find that I can be more expressive and free in my playing if I have it completely memorized.

2. I find that when I am in a situation where there happens to be a piano, and folks ask me to play, I can, rather than having to say "oh sorry, I can't, I don't have my sheet music"

[redhead]

I got my bachelor of music in oboe, and I never memorized anything.  You need good reading skills for all the ensemble work.   I'm sure this colors (for good or ill) my approach to memory on the piano.

On oboe, memorization isn't required for performance.  Even with the most difficult repertoire, memory won't help you hit the notes any better since you gain no benefit from looking at your fingers or at the oboe keys.   I doubt you'd gain any benefits from communicating with others in an ensemble atmosphere while playing from memory.  But I never tested this.  All ensemble playing was with music.

I've never felt any increased freedom from memory.  In fact it is exactly the opposite:  all my freedom has been removed since I'm worried about remembering the notes.

I do find memorizing on piano easier for 2 reasons.  First, there is actually a use in some cases since making fast leaps is easier from memory.  Also, you can use visual memory since you can look the keys.  There is no visual memory with oboe since there is nothing useful to look at.

[puma]

     Some interesting replies and worthwhile stuff said, as far as memorizing goes, I have encountered two schools:  One kind of teacher who says you have to memorize the piece, another who says it is no big matter.  Then these two schools break down a bit - I had one teacher who felt memorization should only be approached once you felt comfortable for the piece, and then only for performance.  And another who thinks sight-reading may actually be better in some circumstances.  As far as a page turner - I have seen some concert pianists employ the use of a page turner for their concerts (which last rather long, you know, say about 1 1/2 to 2 hours) and I will admit the page turner was a distraction for me, but in part because I was pondering, as a pianist, how he built a relationship with his page turner, how it was affecting him, how much he relied on the page turner, how skilled was the page turner, is she getting paid as much as the pianist? etc. etc. so I can't exactly speak for other people on whether it's distracting or not.  What I will say is that his performance was no less powerful than others - when the music came to a crescendo, or suddenly went piano, I, along with the people sitting by me, as far as I could tell, still enjoyed it.  I really don't think of him as being any less of a pianist for having employed the page turner.  It seems to be that it's more impressive to play from memory, but to play with the score will not seriously affect the audience's perception.

[betricia]

Has anyone heard from Bernhard?  I do hope you are OK. Bernhard.  I don't blame you for having a break but maybe you have been around on other threads.  I don't have time to read often but hope all is well.
Patricia

[ShiroKuro]

I've never felt any increased freedom from memory.  In fact it is exactly the opposite:  all my freedom has been removed since I'm worried about remembering the notes.

Maybe what I feel is what redhead is talking about here. I never feel hindered by using the score, and obviously it leaves me free to focus on the music rather than on the notes.

BTW, yesterday I picked one of the easiest pieces in my repertoire and tried to play it without the score (I've always play it with the score, for the last several years)  I got stuck in the middle, or I should say I got confused and just jumped ahead and the finished the piece. Then I took a look through the sheet music, put the music away and the second time I was able to play it through to the end with no problems. But I still prefer having the music on the stand 

[cz4p32]

I have enjoyed reading this post.  To throw in my 2 cents.  For my whole life I have had a problem memorizing, never really liked to do it.  As I got older though, I realized that as was said before, when a piece is memorized well, thoroughly learned, you can play it with so much more feeling and attention to detail.  At the same time, there are pieces that even now, I have the score with me when I play them just as a guide for certain sections that cause trouble.  But with a piece like that, I wouldn't say I have it fully learned.  What i do is play through the piece from memory.  As soon as I get to a section that I consistantly need to refer to the score, I note it, and go back and just work on that section seperately until it's memorized.  Then I start again...hopefully make it though past that previous point.  So that seems to help.  But I think there are times for using music.  And it's interesting that someone as great as Hamelin, has used music in concert.  For example, The People United Will Never be Defeated, he played with the score, and also a performance of a few of the godowsky studies, he used the score.  Not that he couldn't memorize them, but for some reason he felt it ok to have the score and a page turner.  Any thoughts as to why someone of that calaber would chose to perform with a score?

Justin

[quasimodo]

Actually, the paradox is that the more advanced you are, the harder it becomes to memorize, and the issue here is not the memorization skill but the fact that professional pianists have a huge repertoire of pieces (sometimes thousands !) so it's quite normal that with such a volume of pieces in your head, you just might happen to have some confusion between them, a lot of pieces have similarities.

I think that's the reason why some concertists prefer to have the score in front of them : to avoid beginning with a piece and ending with another one  .

[nomis]

But Richter, Myra Hess and Bela Bartok did it all the time!

Ian

Richter and Hess only used scores towards the end of their careers, when they didn't feel confident from playing from memory.

[nomis]

When I first started playing (6 years ago, as an adult) I occasionally played  pieces from memory in recitals, but at some point my pieces got longer and my sight-reading got better, and I got out of the habit of memorizing. Or I should say, until then I had memorized without planning to, naturally, and as memorizing became more difficult because of the pieces, and less necessary because of my comfort with score, I stopped doing it.

Now, reading Bernhard's advice, and Chang's, about how to memorize (and of course always hearing my teacher wonder when I'm going to memorize something) I am slowly trying to incorporate memorizing into my routine.

But I can't help but wonder if I really need to memorize. After careful attention to what I'm doing when I play with the score, I have concluded that after the earliest stages of playing something, I am not sight-reading note-for-note, but looking at the score as a whole, as a memory guide sort of.  There are parts that I look at specifically (kind of like how you might look at the keyboard for a big jump) but in generally I'm just sort of following the grand staff with my eyes (again, not the same as sight-reading or the way we read something for the first time)

People say there are several types of memory, and one is visual. Well, looking at the keyboard is one way to use visual memory, why is it bad to look at the score as another way?

Also, recently I've been trying to keep adding to my repertoire, and I also want to play a selection of Christmas songs every year, so being able to always go back to the score has really helped me. Being always comfortable following the score seems to make it much easier for me to have a playable repertoire as well as keep working on new pieces. (And of course, at the end of Nov every year, I don't have to re-memorize those carols, I just re-read them, which I find much easier)

So my first question is: why memorize if I don't feel like I'm hindered by having to have the score open?

The second question is: Is it possible to take a piece I've played for years, but only with the score, and memorize it now? It seems to me that that is more difficult than memorizing it in the earliest stage of playing it.

Bernhard, I hope you have a minute to give your advice and comments, because I have been putting most of your other suggestions to use, with great results.

It's all down to you really. I much prefer playing from memory, because it's a much more pleasurable experience than from playing from the score. I feel less rigid too, as my eyes are freed from the page and I can close my eyes, and just experience the sound only. Blind people have heightened hearing because of the loss of sight - my ears become more sensitive too (when I close my eyes) as there is much less information being processed by the brain. As a result, I can really concentrate on the sound, and different interpretations might result due to the heightened aural awareness. Or you might notice that you were accenting that E everytime you played that particular passage, and you can fix it.

Many people record themselves playing because they are blissfully unaware of the sound that is being created when they're playing. I find this unfortunate, because if they were to concentrate on the sound, they wouldn't need a recorder. They'll also be able to create the sound they want more easily. Plus, there is also the satisfaction of knowing a gazillion pieces that you can just play on the fly, whenever you want, rather than searching for the sheetmusic first.

[ryno200sx]

Like some of the others above, I do not rely on the sheet music any longer than I have to. I view the score as a tool to help me "get" the piece and although I may refer back to it once in a while, for the most part I don't use it. I definitely don't look at it as I play the piece.

I practice sight-reading in a separate practice session on very easy pieces to help cultivate that skill.

Is there anything wrong with this approach? i.e. practicing sight reading separately from the pieces one is working on?

Thanks,
Ryan

[ShiroKuro]

Bernhard, are you back? Please post if you have a minute and share your views. (a desparate plea!)

[bernhard]

Bernhard, are you back? Please post if you have a minute and share your views. (a desparate plea!)

I have little to add. The posts in this thread have been consistently excellent.

1.   Memorising (that is playing without the sheet music) at the piano is a recently recent phenomenon. Clara Schumann (1819-1896) was the one who started doing it, and everyone promptly called her a “show-off using cheap circus tricks”. Before then, every pianist used a score. Now, of course every pianist is expected to do it, but it seems to apply only to pianists. Every other instrumentalist plays from the score.

2.   Having said that, you cannot play anything properly unless you have memorised it. The paradox here (if we can call it a paradox) is that this “memorising” has nothing to do with the score. Even if you play with the score, if you play it well, you will have memorised it. This means that there is some sort of memory that includes the score. That is, you play from memory, but unless you have the score in front of you, you cannot access that memory. This is not as far-fetched or unusual as it may seem. Some people cannot “remember” how a tune goes, unless they play it. They sit at the piano (without a score) and play the tune perfectly from memory. But if they have to sing the tune (or hear it in their minds) in all of its detail, they cannot “remember” it. It is not that their memory is faulty, but rather that they need to touch the keys to access the full memory of the tune. So in order to play without a score (which as you may have noticed by now is not exactly the same as playing from memory) you must supply yourself with a method to access the memory different from the score. For instance you may have to look at the keys. This means that you will play without the score but looking at the keys. What about playing with closed eyes (an upgrade of circus skills?). You are then accessing your memory through touch and inner hearing.  Or if you have a photographic memory you may “photograph” the score in your mind and play from that mental score (is that cheating?), in which case you will probably not be able to play with open eyes, or if you do your eyes will be “glassed”, since you are looking inwards, not outwards.

3.   Over the years I have become convinced that the only difficulty in piano playing is memorising, in the sense of truly knowing your piece in all aspects. If you truly know your piece (the notes, the times, the fingers, the movements, the structure, the melody the harmony), and all of this by heart (interesting expression to describe memory, don’t you think?) you will simply play it perfectly.  Any problems you may encounter can be ultimately traced back to a faulty memorisation at some point.

So to answer your original question: Memorisation is essential. That may or may not include playing from the score. I do agree with what was said above that being able to play without the score is very convenient.

(And a thought that just crossed my mind, we do expect actors to memorise their lines, and not read them from the script – although nowadays I am sure they use that prompt that news people use).

Best wishes,
Bernhard.

[ShiroKuro]

Thanks (as always) for the interesting comments Bernhard!

You addressed what I was trying to get at by saying that playing from the score is not the same as sight-reading. I think I have "trained" myself (for better or worse) to use/access my visual memory by looking at the score. Another thing I notice is that if I don't have the score, I look down at my fingers a lot more (the whole time maybe!) so maybe I'm really dependent on visual cues.

Ultimately, I think my dilemma remains because it seems (at least for now) to be an either/or situation. Either I look at the score or I look down at the keys. Either I play with the score always or never.

One of my original questions was why memorize if I'm not hindered by using to score? After reading your comments, I think the question could be rephrased to ask something like "am I hindered if playing from memory includes/requires playing with the score?"

Certainly the answer to that would include issues of convenience, especially not having to worry about page-turning and being able to play even if I haven't brought music with me. But the flip side of the answer would be, if I have truly memorized a piece in all of its aspects, and I still have the score out, it's probably not a problem.

So the conclusion I've come to is that I have to answer the following questions for myself: Which is more important, looking at the score or looking down (or maybe which is worse)? How important to me are issues of convenience (page-turning etc)? Lastly, and most importantly, am I truly memorizing the pieces (w/ or w/out the score)? Would I do a better job of memorizing if I did away with the score, or am I doing ok now and doing away with the score would just be a different way of memorizing?

It will probably take a while to answer these questions... I guess I need to follow that other famous piece of advice: "take two pieces of similar levels, do one method for each piece, and compare the results."

[Sasha42196]

I find that memorizing a piece comes naturally as I practice it for hours and days and maybe even months.  In most cases, I won't even realize how muchI have memorized unless I try to play without the music in front of me.  In my experience, forcing myself to memorize something is much harder than just letting it sink in with many repetitions over and over.
I try to play from memory as soon as I can, even if it is a few bars at a time.  Having to look at the music doesn't help when you have a difficult passage to learn.

[pianowelsh]

Ideally every student will have the 'ability' to memorize and will begin doing so from a very early stage.  However life is rarely ideal. The decision to mem or not really has to be with the individual.  It is possible for almost everyone to memorize but it has to be weighed as to the possible stress it will cause. The question to ask is of what reall benefit is it to memorize.  Actually its pretty hard to defend it (in the playing without the copy there sense) it doesnt automatically add anything to the music, it dosent always make the performer more confident in fact often quite the opposite and for some it is seen as just another obsticle to overcome.  The only reall possible argument is the aesthetic one of having a page turner or having the performer not look around so much.  The mistake that is often made is that people use the music because they havent sufficiently learnt the piece to performance standard. People think if i dont have to memorise it i dont need o be so rigerous with every detail to get it into my brain, but actually this is not so. It should merely be a shorthand aide de memoir by performance time and it should be possible for the pageturner to have a heartattack and you still carry on. 

[kilini]

The same thing happens with me, sasha.

Is memorization by learning the same that comes if I just force myself to memorize the piece? Can true memorization be a byproduct of learning a piece well?

 I find that I have a deal of photographic memory as well, for the pieces that I've learned. What Chang describes as products of memorization seem to come after I've learned the piece. In my experience, every piece I've learned thoroughly get memorized. And not just by hand memory.

[Sasha42196]

Well, my problem is that I am not a very good, actually terrible, sight reader.  My major is violin and violin scores are far easier to sight read because you only have one hand to worry about, and no chords (very simple ones).  So, I have not been trained to sight read for piano and that has been a real challenge.  So, thanks to a good enough memory and ear, I am able to hear the music in my head and pick the right notes even if I don't have time to look up at the music.
The issue I face is that my memory is not perfect and if I don't come back to the score often, I start omitting notes, or making mistakes in timing, etc.  So, yes, memorization is key but unless you are perfectly confident that you have memorized your piece 100%, don't put away the sheets.

[squinchy]

One thing I discover is that when I begin to try memorizing pieces, I become more conscious of fingering, a thing that has always given me trouble. Also, when I memorize, I first give myself some little points to remember to help the rest of the piece fall into place. Regardless of whether that's the scientific way to memorize, having to think of those points makes playing the right notes easier. After a piece is memorized, one has the luxury of not turning pages (and risk it falling off the piano) or having to refer to the score.

My teacher said that when she was a little girl, her very-strict-very-European teacher made her memorize everything, exercises included.

[vera]

It all comes down to this: How effective does your memory work. If you have no trouble ever, and in concert-situations you always feel free to express whatever is in the music, and you can honestly say, that you do not have any scary moment, that distracts you from the expression, by all means play by memory as much as possible.
If you however belong to those, whose memory never can be relied upon entirely, and you may have tried all the tricks in the book to secure it, do not waste any more time on it. Learn to work around it, organise a page-turner, indicate precisely, where to turn, practise with the page-turner. but if you cleverly arrange your music, bits of copies stuck to the page here and there, you may do it yourself.
I have been in the last camp for many, many years. But I have also tried and done concerts by memory for many years. It was compulsory during my studies, and I kept at it until my late 30s. There was always stress involved, worry about losing it, and this was a massive distraction from the performance. In hindsight I can now say that I did not like performing all that much then. But I thought, this is how it is, and I have to accept it. In my late 30s I gave up memory playing altogether, and what a joy have the concerts been since. Total freedom with expression, stage- fright disappeared immediately. In my 40s and up till now(58) I have done more concert work than ever, and it remains great fun. There may be a few disadvantages. What do you do, when you have no music with you and people ask you to play? Well, there are some old war-horses still hidden in my memory from my teen-years. I dig those up usually reasonably ok. If you think, you may get asked, always carry some copied pieces. It is no big deal. Much the same as needing spectacles. You just work around it.
What I don't buy, is that you produce always better quality, when playing by memory. It was always the opposite with me, and I suppose will be the same with others like me.
But I intensily dislike the pressure others put on people like me, to force them to do it, just because it is the thing to do, and because they believe it makes you play better. If they think it works for them, fine, but do not force it upon others, just as I do not force my viewpoint on others.
Of my students, some happily play by memory, some do not, although I do encourage them, to at least have a try. I am amazed, how good some children's memories are. But those are the exception rather than the rule. Most have to really work at it.

[Groggy60]

I am an excellent site reader with very poor memorization skills. I feel extremely comfortable and relaxed playing pieces with sheet music. My hands "learn" the music as a play a piece repeatedly and work on it, so I am not site reading after a few plays. This level of memorization lasts a long time, even decades.  With the few pieces I have memorized, I play them with much more feeling and understanding when I use sheet music.  Public performances and page turners are not a issue for me.

I disagree that a piece must be completely memorized and played without sheet music to be really understood.  Sheet music is my medium. I don't see a piano when I think of piano music, I see music on a page.