There are some cases: the case where processes until the manufacturing process of koji are outsourced; the case where non-heat-treated soy-sauce supplied by large manufacturers is used for heating and packing, omitting processes until the preparation process; the case where orders are placed to large manufacturers as OEM.
製麹工程までを外部に依存するケース、仕込工程までを行わずに大手生産者より生醤油を購入し、火入・詰工程を行うケース、OEMとして大手製造者に発注するケースがある。