Matazaemon V incorporated the Marusan Beer company founded by his predecessor and took on the role of president. He built the modern Red Brick Brewery using the latest brewing equipment and ingredients imported from Germany, ensuring authentic beer production. The brand name was also changed from Marusan Beer to Kabuto Beer. Unfortunately, the beer industry was in a period of cutthroat sales competition. Kabuto Beer made a valiant effort despite competing against brands backed by significant capital, such as Nippon Beer (Yebisu), Osaka Beer (Asahi), Japan Brewery (Kirin), and Sapporo Beer (Sapporo).

In 1906, the giant Dainippon Beer Company (which was split into the current Sapporo and Asahi after World War II) was formed through a merger. Observing the trend towards trust formation, Matazaemon V decided to change direction and sold the beer business. This decisive move helped prevent future financial difficulties.

Integrating cutting-edge beer brewing techniques into the traditional vinegar-making industry proved highly beneficial. For instance, modern equipment was installed in the new plant (Minamikura) built in 1900. This marked the first step towards comprehensive mechanization. In the same year, employees were sent to Germany to learn about advanced brewing technology. In 1902, after their return to Japan, Matazaemon V opened a brewing research laboratory dedicated to improving vinegar brewing technology. The expertise gained from the beer business brought immeasurable benefits to the core vinegar business.

Matazaemon V was a man of solid integrity, but he was not satisfied with the status quo and worked hard to strengthen production bases in both the east and west of Japan. In 1905, the Amagasaki Plant was established as a production base in the Kansai region, supported by a series of loans backed by Nakano Bank.

To establish a production base in Tokyo, the company participated in the joint management of a vinegar plant and established Marusu Limited Partnership in 1919. However, that same year, Matazaemon V suddenly passed away, leaving his vision and legacy to Matazaemon VI. A few years later, the jointly managed plant became the Tokyo Branch Plant operated directly by Nakano Sumise.