This would have been an email to Edrei but I thought it would be good to share.
You should read this first, to get a good idea of how to do a cube blindfolded:
As of time of writing, I have not ever solved a regular 3x3x3 Rubik’s Cube blindfolded (definition: you get to look at it once, then when you look at it again it must be solved, and the cubes are all equal size, texture and shape to avoid differentiation by touch. The Rubik’s Mirror has cubes of different sizes and I can solve that blindfolded.)
I was hospitalized for contact dermatitis – I’m fine don’t worry, and I’m out of the hospital already! So I took the time spent there to learn how to do it blindfolded.
I use the Stefan Pochmann method as described in the link above, where you swap two pieces at a time, and remember which pieces to swap. I would either solve all edges first or all corners first.
Each corner sticker is given a letter. Each edge sticker is also given a letter. Since there are 24, it seems right to give each one an alphabet!
This assumes you have a proper Rubik’s Cube where the yellow is opposite white, red opposite orange, blue opposite green, like in the picture. You can choose any method of distributing the letters on the stickers.
There are only two formulas to truly learn – the T-Permutation and a (modified) Y-Permutation. The T-Permutation works on the edges while the Y-Permutation works on the corners.
The T-Permutation and (modified) Y-Permutation are actually made of 2 same sequences!
Sequence 1 = RU R’U’R’ FR
Sequence 2 = R U’R’U’ RU R’F’
The T-Permutation is Sequence 1 then Sequence 2.
The Y-Permutation is Sequence 2 then Sequence 1.
The T-Permutation swaps UL and UR edges, and UFR and UBR corners. UR is the source piece, so move the target ‘slot’ into UL in any way you prefer on the condition that you not displace UFR and UBR!
The Y-Permutation swaps LUB and DFR corners, and UL and UB edges. LUB is the source piece, so move the target ‘slot’ into DFR in any way you prefer on the condition that you not displace UL and UB!
So in an example cube, I would do the corners by looking at the corner with Q first, then seeing what is the corner piece with the V sticker, and determining where it should go. An example sequence:
Then I would work on the edges, for example:
There was a closed cycle, which is why it took longer – on a good day you’d only have to remember 10 letters. For some reason, remembering them on my fingers seems to help. Remembering is not the problem – screwing up on one of the sequences, or doing the wrong reversal steps e.g. moving edge T to position in B via the back face and reversing the steps via the front face!
I have done a complete edge-only blindfold solve (very hard) and a complete corner-only blindfold solve (less hard since there are less corners than edges.) I have yet to commit to memory both a edge letter sequence and a corner letter sequence. Ah, there is so much to practice!