After Dark is a minimal chair created by Japan-based designer Toshiki Omatsu. One would be in an unsettled mood when you sit inside the semicircle, which one rarely sits on. On the other hand, by making the seat surface a semicircle, the armrests are integrated directly into it the structure, and it defuses one’s tension as if being wrapped. Sitting in this chair gives the user such a complex feeling of tension and defused friction. It may resemble a chair for sitting alone in the dark. The studio wanted to make the plate thickness as thin as possible in order to give the feeling that the seating surface of the semicircle is floating in the air. The thickness of the aluminum plate used is 4mm thick for the seat surface, 6mm thick for the side plate, and 10mm thick for the two members that cross each other while supporting the seat. Initially, the thickness of the side plate was 4mm, but it was found that welding of 4mm and 10mm thick members causes distortion of the side plate.