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Seiji Yamashita

Seiji Yamashita

From elementary school to university, I was devoted to baseball and worked hard in both the literary and military arts.

Even now, my experience and connections in baseball are of great help to me in business.

After graduating from university, I entered graduate school for accounting, and then held positions such as managing director (system officer) at a company listed on the first section of the Tokyo Stock Exchange.

After becoming independent, I worked at a law firm to obtain tax accountant qualifications.

We established TREASURY Co., Ltd. in 2016 to contribute to the world through IT and professionalism.


The business started with web advertising and system development business, and in 2019, the electronic contract service "Great Sign",

In 2022, we launched the online identity verification service "Great eKYC."

In addition, we employ excellent global human resources as our in-house engineers.


In business, we mainly conduct business related to DX while collaborating with professional teachers, governments, and companies all over Japan.

We not only provide systems and services, but also work together with everyone to improve literacy and make the world a more convenient place.
While conducting business related to DX, we are also strengthening our efforts in regional revitalization, sports promotion, and social contribution.

Currently, we are conducting IT business mainly in Japan, but also in Singapore, the Philippines, and Vietnam, and we will continue to aim to expand our business globally in conjunction with Japan.


Born in Ehime Prefecture in 1976. He has held positions such as managing director at a company listed on the First Section of the Tokyo Stock Exchange, and is working at a law firm in order to obtain tax accountant qualification. Established TREASURY Co., Ltd. in 2016. In 2019, we started the electronic contract service "Great Sign."







Born in Ehime Prefecture





Established TREASURY Co., Ltd.

Launched electronic contract service "Great Sign".

オンライン本人確認サービス「Great eKYC」をスタート

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