Thinking ahead when sight reading, or when playing from memory ...

I've spent a lot of that twilight time half way between sleeping and waking musing on why it's so difficult for me to think ahead when I'm sight reading.  I know that the only effective way to sight read is to read ahead, but except in the simplest examples I just can't seem to do it.  I become totally absorbed in the note that is playing now, with the result that what comes next can be a complete mystery until I have to play it - with inevitable consequences.  No matter, I console myself.  I'm OK at memorizing and I don't need to sight read (much) at this stage.

And then came the Bach piece, for which I am thankful, really I am.  It's not a hard piece with multiple simultaneous voices - indeed most of it is single line music.  And although it presents some unique challenges for me, I shouldn't have any problem memorizing it, right?   Wrong.   Despite learning individual sections fairly well, when I try to string it all together my mind goes AWOL at random places.  What on earth is going on?   "It's just Bach" people say - but that doesn't explain why it's causing me such a problem.

I set out to see if I could figure out a way to overcome this mental ditziness.  The first thing I tried was actually reading the music ( I know, not my thing) while playing.  This led to the usual issue I have, which is I'm not good at playing without looking at my hands, and of course I can't look at both at the same time.  OK - I thought - I can remedy that - I will practice the piece with my eyes closed - there must be large parts of it I can actually play without looking, I'm just not used to it.   I did have the usual problems with hitting the right place on shifts, but apart from that, a very strange thing happened - I wasn't forgetting where I was. In fact I found myself actively visualizing what was coming next.  Which led me to the realization that this is unusual for me - even when playing from memory I am focused on the here and now and not what is coming next.  There is evidently something about staring at my hands that stops me thinking ahead.  This explains why I sometimes "lose my place" - no doubt exacerbated in the Bach where the different phrases have so many features in common that if muscle memory fails I can't instantly figure out what's up next.

Of course this leads me to an unfortunate realization that in order to better learn pieces, I first have to be able to map my left hand to the fretboard without looking.  This is something I've avoided rather successfully up until now.  Best case scenario - maybe I don't have to totally learn not to look, instead the attempt to play without looking will retrain my brain to think ahead.   We shall see.