O-nigiri(お握り or 御握り; おにぎり), also known as o-musubi(お結び; おむすび), nigirimeshi(握り飯; にぎりめし) or rice ball, is a Japanese food made from white rice formed into triangular or cylinder shapes and often wrapped in nori (seaweed). Traditionally, an onigiri is filled with pickled ume (umeboshi), salted salmon, katsuobushi, kombu, tarako, or any other salty or sour ingredient as a natural preservative. Because of the popularity of onigiri in Japan, most convenience stores stock their onigiri with various fillings and flavors. There are even specialized shops which only sell onigiri to take out. Due to its popularity in Japan, the trend of small restaurants selling onigiri has traveled to the American West coast, specifically California.