Opanka is a sandal-specific design that connects the top to the outsole by enlarged material lips connected together by stitching. The upper comprises two separate parts: the toe and heel areas are one piece of leather or synthetic material, while the midsection is made up of several sections secured with straps and/'ties. Opankas were first created in Japan in the 1950s and have been popular ever since. The word "opanka" is Japanese for "sandal". Sandals were originally just pieces of wood with a strap around the foot, but over time different materials were used instead. In the case of the opanka, the sole is attached to the shoe itself using sewing or hot gluing. Today, many variations on the theme exist, including ones with plastic or rubber soles. The creation of the opanka was done with the bamboo tree in mind. Bamboo can grow very fast and its soft tissues can be used for making shoes, clothes, and other products. The large number of uses for this plant has led to it becoming popular again as a sustainable alternative to traditional materials like leather and fur. It is estimated that if used globally, bamboo would be enough to cover the earth's surface three times.