Zōri (草履?) are flat and thonged Japanese sandals made of rice straw or other plant fibers, cloth, lacquered wood, leather, rubber, or—increasingly—synthetic materials. Zōri are quite similar to flip-flops, which first appeared in New Zealand and the United States sometime around World War II as rubber imitations of the wooden thong sandals long worn in Japan.
The traditional forms of zōri are seen when worn with other traditional clothing; modern forms are fairly common, especially in summer. While geta are nowadays worn with the informal yukata, zōri are associated with the more formal kimono. The formality of the occasion affects the choice of kimono and zōri. The bulrush covered zōri that resemble tatami mats are not used with kimono, but are considered working wear or matched with casual Western or Japanese clothing, for example jinbei. Thus they rank close to the wooden geta.
Women's vinyl (plastic) zōri are formal, but less formal than fabric, sometimes brocade covered zōri, that are used with the most formal of kimono, for example, wedding and funeral wear. Men's zōri are often plastic straw imitation, with foam or cork soles. The hanao, or thongs, for men are often white or black. Women's zōri can also be of straw imitation, but the hanao are usually red, and they rank below colored vinyl or brocade zōri in formality. As formal wear, all plastic and fabric zōri for women require the use of white tabi socks. Men have more latitude, and can use the same imitation zōri with both informal (without tabi) and formal wear with tabi socks.
The hanao is attached symmetrically, so there is no difference between left and right shoe. The hanao of zōri can be made of velour-like material, as in the case of plastic straw imitation zōri. The hanao for more formal coloured vinyl zōri are either thin vinyl or brocade straps, or wider and padded vinyl or fabric straps. The fabric is often either the fabric used for the shoe, or chirimen, crepe-like Japanese silk or rayon fabric. Men's zōri might also feature leather or leather imitation hanao. The hanao wear and stretch easily, and the hanao fashion and the coordination of accessories sometimes calls for replacing the hanao. The hanao can be replaced through flaps of the sole.