This article was written by Nicolas Gregoriades, who is a 3rd degree Jiu-Jitsu black Belt under Roger Gracie. Nic is an instructor at Subconscious Jiu Jitsu.
Grappling with your eyes closed is an excellent method of gaining sensitivity, balance and timing. When you close your eyes, you lose the balance granted to you by the visual reference points you usually have. As a result, the organs in the inner ear responsible for the body’s equilibrium become more finely tuned and your sense of balance increases. This, in turn, improves your kinesthetic awareness or ‘body sense’. Spatial awareness, the ability to know where your body is in space, is also massively enhanced. High levels of kinaesthetic and spatial awareness are hallmarks of good athletes and are some of the most vital elements into a well-rounded game.
Your skin contains millions of pressure receptors, and when your eyes are closed it becomes much easier to be aware of the input they are receiving. This will allow you to 'feel' your jiu-jitsu more - to become more sensitive to the subtle variances in the weight distribution of both yourself and your opponent.
When you are fighting from the top, the increased sensitivity will allow you to feel where the gaps are in your control positions and hold-downs and when fighting from the bottom it will be possible for you to sense where your opponent is applying pressure and where he is off balance and susceptible to sweeps and bridges.
Because this pressure-sensory data is processed much more quickly than visual-sensory data if you can teach your body to use it as your primary feedback mechanism while fighting, your reaction times will ultimately improve.
Yet another benefit of practising in this manner is that when your eyes are closed you have a tendency to relax, which as explained elsewhere in this resource, is vital to your grappling progress. So pick a training partner who you trust and grapple with your eyes closed for 20-30 minutes per week. You'll be astonished at how much it improves your game.