This glaze makes use of umeboshi or ume plums, a small Japanese plum that is usually pickled whole or processed into a paste. The spiciness of fresh ginger and sake round out this unique glaze that is particularly ideal for oily and fatty fish such as salmon or sardines. As with any wine or liquor used in cooking, use the best quality sake you can find to deglaze the pan in this recipe—ideally one that would traditionally be consumed hot rather than cold.