Japanese soy sauce (shoyu) is made from a mixture of soybeans and wheat which is mixed with salt and water and an active culture called koji. This is left to brew slowly for at least a year. Shoyu is used to some degree in most Japanese dishes including hot-pots, noodle dishes, soups and sushi.

Related recipes:

Japanese pan-seared salmon with soba noodles
Japanese rice pot with shrimp and vegetables
Sushi rolls
Teriyaki chicken noodles
Soba noodle scallops
Japanese-style grilled marinated tuna with wok-fried soba noodles