When ever you try to play Crazyhouse blindfolded on lichess, the board is blank and as the game progresses you see that you can see the pieces in hand at the right.
Some might argue ZH-BLD will be true blindfold if the pocket is not visible, but counting the pieces just gets too hard, and I think it is almost two board worth of information that you have to keep track of.
White does have a significant advantage in ZH, and 1.e4 has been played dominantly uptil now. So, most of the opening prep for ZHBLD from white will be e4e5 openings or some sidelines of it.
Gaining more positional understanding is important (identifying weaknesses and potential threat mates) to memorise the board. Also calculating mate skill is much more important if you are blindfolded, as you do not want a game that drifts away or the opponent gets a chance to swindle.
Key areas to work to get ZHBLD playing strength almost equal to normal ZH strength can be:
1) Calculating mate
2) Understanding more lines and sidelines in openings
3) Able to memorise ideas and weaknesses and also create them on the board, while keep the track of how much the position might change.
4) Treating each position as new, whenever a move is made.
5) Practising normal chess blindfolded, to make life easier and increase chances of not giving up.
I am planning to continue developing a rulebook for playing ZHBLD for beginners (1800-2200), so that it becomes to try it out early before becoming super strong. Best ways is to get thematic examples, and how the thought process will go when we are blindfolded.
Crazyhouse Blindfolded 960 is just too hard, but it can be tried out at pychess.org, and changing the board settings to invisible pieces and playing Fairy-SF by selecting a challenge of ZH960.
