Nike has enlisted Japanese knit brand Loopwheeler to assist in adding indigo-dyed material to the Air Force 1 Ultraforce and Sock Dart. The design for each of the shoes is inspired by the Japanese indigo dyeing tradition known as Aizome, a method they’ve practiced for over 1,400 years. Though it’s a challenging process, Loopwheeler color-blocked the shoes with two indigo-dyed layers of fabric: one layer is entirely dark indigo, while the other is indigo-dyed, heathered white cotton. That same heathered cotton lines the inside of both shoes, as well. Loopwheeler’s logo is on the tongue of each shoe, and the Swoosh is completely indigo-colored on both offerings.

The Loopwheeler x NikeLab Air Force 1 Ultraforce and Sock Dart will be available July 16 via Nike.com, NikeLab MA5 in Tokyo, and Loopwheeler stores in Tokyo, Osaka and Fukuoka.