| 1891Meiji 24 |
The founder, Toranosuke Ohtsu, studied under Mr. Shigemoto who were called a “master craftsman of koto” living in Ueno, Tokyo. |
| 1901Meiji 34 |
Toranosuke became independent from Mr. Shigemoto. He resided in Ushigome-ku, Tokyo (currently Ushigome, Shinjuku-ku, Tokyo) and started retail sales in addition to the main koto crafting. Then, his four sons started koto crafting one after another. The first son, Kiyoshi Ohtsu, started business in Ueno, Taito-ku, Tokyo (Negishi). |
| 1938Showa13 |
Hiroshi Ohtsu, Toranosuke’s fourth son, took over and became the second president of the shop in Ushigome, Shinjuku-ku. |
| 1943Showa18 |
Hiroshi and his family evacuated to the current Ohta City, Gunma Pref. to escape war damage. |
| 1966Showa41 |
Hiroshi relocated the shop to Komaba, Meguro-ku, Tokyo. |
| 1976Showa51 |
Relocated to Daizawa, Setagaya-ku, Tokyo (Shimokitazawa). The business was incorporated as a private limited company and named Ohtsu-kotosangen, Co., Ltd. Hiroshi’s second son (the third generation), Hirotsugu Ohtsu, became the president. |
| 1992Heisei4 |
Hiroshi (the second generation) was certified as the traditional craftsman in Tokyo. |
| 2004Heisei16 |
The company registered as a competitive bidding company of Tokyo. |
| 2005Heisei17 |
The company launched website to provide information about kotos. The successor’s second son, Ryo Ohtsu, started participating business operations and continues to the present date. |
| 2006Heisei18 |
The company acquired the antique dealer permit. Tokyo Metropolitan Public Safety Commission Permit No. 303260609232. |
| 2007Heisei19 |
The company launched the recycle market. |
| 2009Heisei21 |
Hirotsugu Ohtsu (the third generation) was certified as the traditional craftsman in Tokyo. |
