What is this true meditation?

It is to make everything: coughing, swallowing, waving the arms, motion, stillness, words, actions, the evil and the good, prosperity and shame, gain and loss into one single koan . . . with the principle of pure, undiluted, undistracted meditation before your eyes, attain a state of mind in which, even though surrounded by crowds of people, it is as if you were alone in a field extending tens of thousands of miles . . . if at this time you struggle forward without losing any ground, it will be as though a sheet of ice has cracked, as though a tower of jade has fallen, and you will experience a great feeling of joy.

~ Hakuin