Temposchlucker asked me: I assume you have tried to play blindfold chess. What's your experience?
I have to confess that I did try a lot of methods to improve my visualization and calculation. And amongst those was also playing blindfold chess. I was not very good at it. I managed to play blindfold without playing illegal moves, but it was not something that came naturally.
The way I played was that I would reconstruct the complete move sequence from the first move onwards, to rebuild the chunk I wanted to analyze. When I had done this (I did this fairly quickly) I was able to analyze the position a bit.
As far as I can remember I never felt that I improved. Not in playing blindfold, nor in regular OTB games. The only thing that made me better in visualization is the platform technique that Tisdall described in "improve your chess". Not that it made my visualization and calculation deeper or faster, but mainly because it made it more effective and efficient.