In ancient times, tamari was simply the dark liquid that pooled on the surface of fermenting miso. Tamari that is collected from miso dates back to eighth-century Japan and may have originated in China. By 1290, the first commercial tamari shop was established. Gradually, central Japan, because of its ideal climate, choice soybeans, and high-quality water, became a tamari center. Around the fourteenth century, a purposely wetter soy miso was prepared; after fermentation, its flavorful liquid was pressed out, filtered, and bottled. This was the beginning of Japan's small tamari soy sauce industry, which survives today in the Aichi, Mie, and Gifu prefectures. The original thick, concentrated tamari that is closely associated with soybean miso contained no wheat and had a ratio of 10 parts soybeans to 5 parts water. This so-called Go-bu tamari is expensive, time consuming to make, and requires skills that can only learned over generations and must be passed on from one touji, or brew master, to another. In present day Japan Go-bu tamari is a dying tradition and only a few old dedicated producers have survived. Shoyu, which is a more recent and more widely used soy sauce, is a different, but related produce that contains wheat.