It's rare for someone to be able to play blindfold chess without any prior training. Therefore, this service helps users gradually become accustomed to blindfold chess by progressively limiting the visual information available from a standard chess game.
For example, on the game screen, there's a form for submitting moves, but you can switch tabs to peek at the board.
If you find yourself unable to visualize the board, please make use of this feature.
Furthermore, the display of this board can be customized in the settings. For instance, it's possible to make all pieces a single color.
While this might cause some confusion, it's less difficult than complete blindfold chess, so getting used to it from this stage is one approach. Additionally, there's a feature to change all pieces to stone-like silhouettes instead of their usual appearance.
With this, distinguishing pieces becomes impossible, and only the squares provide clues, significantly increasing the difficulty.
These are the specific features that allow you to limit visual information.