**5. Discussion**

Sekiya used to brew sake that relied on an external Toji like any other sake brewery. Most Toji were so-called migrant laborers. They made rice in the summer and worked at sake breweries in the winter. Considering the period necessary for making rice, external Toji could stay at a sake brewery from December to March. Sekiya hired Toji from Niigata, a site of mass rice production. However, Sekiya faced a difficult situation, in that migrant Toji from Niigata markedly decreased after 1993 because of aging. Inevitably, Sekiya switched to brewing sake by employees, and Sekiya was the first company to make sake without external Toji in the

When introducing the brewing system by employees without external Toji, the problem of techniques and skill transfer of high-skilled professionals is often raised. Sekiya was no exception to this problem and had modified this system for three generations. Advancing digitalization attracts a strong impression that machines substitute for the work that laborers do by hand, but what really matters is something else. Laborers, particularly experienced craftsmen, have sharpened senses. It is necessary to install sensitive information into the machine to optimize the next process. This is why computerization of sake brewing through mechanization was a difficult challenge. However, Sekiya has tried for years and achieved the ability to make

Furthermore, the great advantage of digitalization and mechanization was a new brewing system for making sake three times a year. As mentioned above, the usual brewing period allows sake to be made only once a year, from December to March. Sekiya does three rounds of sake brewing within 10 months, except in July and August, when it performs maintenance

Another achievement that should be noticed with the introduction of digitization is improvement of the labor environment. Sekiya employees go to work at 8 AM and leave before 6 PM. Therefore, unlike in ordinary sake brewing (especially among Toji), there are essentially no night shifts.

Sekiya started an original sake brewery with a custom-made system. Very few sake breweries have a custom-made system. Sekiya's second factory, Ginjo factory, was built for the system in 2004. The Ginjo factory's capacity is only one-tenth that of the main factory. In the main factory, 12,000 l of sake are made in one lot. The Ginjo factory originally aimed at making small quantities of many varieties. A small tank serving as a single unit uses 60 kg of rice and produces approximately 100 l of sake. Sekiya receives a wide range of orders from individual

At the beginning of this project, there were very few orders. However, the custom-made system has gradually expanded into the market, and the current number of orders is approximately 220–230 tanks annually. Major customers are brides and grooms and their families, companies, and individual groups who want to celebrate their memorial anniversaries. These customers can send their original sake to someone as an expression of gratefulness and celebration.

consumers, companies, organizations, and restaurants in units of 720 ml × 100 bottles.

Aichi prefecture.

on its machines.

sake of high and more stable quality.

68 Digital Transformation in Smart Manufacturing

**4.4. Introduction of custom-made system**

Customers can select a favorite container, label, and box.
