This is a double-brewed shoyu (aka saishikomi shoyu). Double-brewed shoyu are made the same way as a 'normal' koikuchi shoyu, but instead of adding salt water to the soybeans and koji, they add shoyu instead. The salt helps to protect the fermenting mash, allowing it to slowly ferment for 2 to 3 years. This style of shoyu is made with twice as much soybeans+wheat and takes twice as long to make as a typical koikuchi shoyu so it's thicker, darker, and stronger than a typical shoyu, but it generally has softer flavors and tastes more fruity and fermented. This is a great style of shoyu to use with delicate sashimi or to season light broths as it won't overpower these kinds of flavors. It also makes for an ideal shoyu for dipping.

Suehiro is a traditional shoyu-brewing house based in the heart of usukuchi-shoyu-country. They have been brewing shoyu since 1879 and they remain commited to brewing in small batches, using only Japan-grown wheat and soy beans, adding only sea water and koji besides.

In general, in Japan, shoyu is used in the place of salt; it's sort of an umami-rich salt. So definitely adjust the amount of salt you add to your dishes if you plan to use shoyu. 

5.01 fl oz (This is small, but this style of shoyu is usually used as a finishing shoyu or a dipping sauce. Please refrigerate after opening)

From Tatsuno City, Hyogo, Japan