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 05. Garments for Sitting
Garments for Sitting You will not be comfortable with any kind of tight, heavy or hard fabric clothing when you sit in zazen. Therefore, any loose fitting garment made of fine, soft fabrics will be better in sitting. When you do zazen, wearing garment is much better than wearing nothing.