The walls and ceiling are covered in recycled aluminium panels, originally developed as parts for cars.
Here's some more information from Yoshioka:
"PLEATS PLEASE ISSEY MIYAKE / AOYAMA" was reopened on 1 September, 2009.
This redesigning project has been carried out based on the conservation of interior, which I had designed before by using recycled aluminum material initially developed as an auto-part.
Issey Miyake's conception is to reincarnate the space as "PLEATS PLEASE ISSEY MIYAKE / AOYAMA" by conserving the existing space with recycled aluminum in order to have it transcend the time.
My proposal to his conception is to use a huge lighting wall.
The lighting wall serves to accentuate the nature of the material and interfuses modern technology and light.