i'm working on prelude and fugue XXI for a competition, and i only have 1 month to completely memorize it and have it perfect, so i was just wondering if anyone had any like... miracle tricks that could cut time on memorizing (besides the basic ways you are supposed to learn bach)
Make sure you mark on the entire score when the hand moves to controls a new group of notes and which note acts as the balance point for the hand. This might be obvious to you just by looking at the music but make an effort to highlight it. It makes it overall easier to memorise your music if you make this conscious observation and mark it on the score. It makes you realise which hand is easier than the other in the given section and thus which hand can be easily be played while we focus our full attention on getting the other hand together with it.
When learning Bach I always make it a habit of playing together straight away. But how? One hand should cue the other, one hand should be your solid guide while the other you fully focus to weave between it. Of course the guide hand is constantly changing hands, it is never just one hand all the time, it depend on the notes. To me the guide hand is often the hand which doesn't have to move as much during the passage, or it could be something which is a repeated pattern or a particular voice.
The "guide hand" is understood by your inner ear, it is controlled with sound memorisation, which is your evolved muscular memoristation of the passage. Simply this means you can play the guide hand without thinking of the notes but rather the sound you produce. You
hear if you are playing the guide hand correct rather than put any focused conscious effort on the physical action of the notes. You must be able to listen much more carefully to the guide hand while practicing so that you can use it to queue the other hand.
This mastery of listening to your guide hand should extend to the other hand as well, however the difference is that the other hand never has a chance to be appreciated seperately but rather as a body working within the other hand. So that when you learn to attain ear memorisation of the other hand it is done by observing how it interacts with the other hand, not alone.
This is a different realisation when you play Bach, to forget about the notes, which in reality they are very simple (in terms of amount of notes). But the sound produced is extremely complicated and we do find it difficult to forget about the notes with Bach and appreciate the sound. But as soon as we start appreciating the notes that our hands play as one body of sound we find we memorise passages much quicker. As soon as we observe how chunks of sound in one hand weaves togehter with the other and forget about the actual notes we realise, wow I can play it now. This is so hard to put in words! arrg.

Which book from the WTC is ur prelude and fugue from?