Tsurubishio is a double-brewed Japanese soy sauce of the saishikomi style, made by Yamaroku Shoyu on the island of Shōdoshima in Kagawa Prefecture. It is fermented and aged in traditional Japanese cedar vats known as kioke.

It is made with Japanese Enrei soybeans, wheat from Hokkaido, and sun-dried sea salt from Mexico. After the first fermentation and aging, the unpasteurized soy sauce is returned to the vat, where it replaces the brine in a fresh mixture of soybeans and wheat. The second fermentation and aging take another two to three years, bringing the total production time to about four years. The fermented mash is then slowly pressed under weights.

Tsurubishio has deep umami, a gentle sweetness, and a rich, rounded flavor. It can be served as a dipping sauce for sashimi or drizzled over a grilled steak just before serving. A few drops over vanilla ice cream create a sweet-and-salty combination reminiscent of the glaze on Japanese mitarashi dango.