When Yang-shan Hui-chi (807-883), as a young monk, paid a visit to the Ch'an master Hsing-k'ung, there was a monk who asked Hsing-k'ung:
-What is the meaning of the Patriarch's coming from the West?
ZAZEN MEDITATION GUIDE - Chapter 04. Cushions and Pads
Cushions and Pad You will need a cushion and a pad in sitting zazen. The pad is about 28 inches square, stuff with kapok or cotton batting so it will be about 1.5 inches thick. The cushion which is stuffed kapok or cotton batting, too, and about 12 - 18 inches in diameter and it flattens out like a pillow to set upon the pad. You may use a pillow if you wish.