YAGITA, HAMANO & MORITA International Patent Office

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Our Firm History


Mr. T. Kusaba

Mr. T. Kusaba

In 1901 Mr. T. Kusaba (1875-1949), founder of this firm, entered the office in Japan of Mr. William Silver Hall ( -1906), a British gentleman, as his office manager. At the death of Mr. Hall, Mr. T. Kusaba himself opened an office under the name KUSABA & CO. and continued to practice on his own as a patent attorney, on behalf of foreign applicants. The business of the office was transferred to his son Mr. A. Kusaba (1901-1978).

Mr. Y. Kanamaru

Mr. Y. Kanamaru

At the end of the last war Mr. A. Kusaba started patent attorney's work first in Japan. Due to heavy pressure of work he fell ill in several years when he retired from the first line of business but remained as advisor of the office. Practically the office was taken over by Mr. Y. Kanamaru (1899-1975), Mr. A. Kusaba's cousin and partner, who worked for the office as a chemical engineer and patent attorney since 1930.

Since procedures to the Patent Office have to be taken in the name of proprietor of a patent office we had domestically used our firm name "Kanamaru Patent Office". The name "Kusaba & Co." had been used in all international correspondence since the establishment of our firm.

Mr. Kanamaru died in 1975 and Mr. A. Kusaba in 1978, and we were compelled to change our firm name to "Asauchi & Co." both internationally and domestically, using the name "Kusaba & Co." in parentheses after "Asauchi & Co." under which the firm had been operated for more than 70 years.

Mr. T. Asauchi retired from the office due to poor health. The business of the office was transferred to partner Mr. Shigeru Yagita in November 1980 and the firm name changed to "YAGITA HAMANO & MORITA."

Mr. Shigeru Yagita died in 2004 and the business of the office was transferred to partner Mr. Takao Hamano in November 2004.

The business of the office was transferred to Mr. Satoshi YAGITA from Mr. Takao HAMANO in July 2021.


As almost all patent attorneys' offices do we prepare and file patent, utility model, design and trade mark applications in Japan and abroad for Japanese clients and clients from other countries. Also we issue expert's opinion if required, and handle infringement and licensing cases.

We are qualified specifically in mechanical, chemical, biochemical and electrical fields. As to the fields of technics in which we work, however, we can say that we can handle applications in nearly every field of technique. Our staff members have not only a juridical but also a very broad technical education and experience, and further more, every diversified specialisations.

Being one of the oldest patent attorneys' offices in Japan, we can boast of a history which we believe to be unparalleled in Japan not only in the very large number of cases we have handled up to date but also in that these cases for the greater part have been prosecuted on behalf of overseas clients.

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