Ho So said:
If you are hungry take food, but leave off before repletion.Then ramble about for long distances and make your stomach empty. Then enter into a quiet room, sit down in the correct posture and be silent. Count your inhalations and exhalations, beginning from one to ten, then on from ten to a hundred and from a hundred continue to one thousand. You will then find that your body will be as still and your spirit as calm as the void itself. When this state has been reached and has lasted for some time your breath will automatically stop. When your breathing in and out has stopped, your breath will come out like a steaming cloud of vapor from all the eighty-four thousand pores of your body. Then all illnesses, permanent and chronic,will automatically be eliminated and you will understand clearly that all your troubles and handicaps have been destroyed in a most natural way. It will be as if a blind man had suddenly received his sight; he will no longer have to ask someone to point out the way to him. All that you have to do then is to give up worldly speech and sustain your vital energy. For it is said: He who nurtures the eye-sense always keeps his eyes shut, he who nourishes his ear-sense is always sated (by noises), he who nourishes the heart is always silent.
-from Hakuin-Zenji's "Yasen Kanna"