| Watanabegumi Co., Ltd. | Sato Road Co., Ltd. |
| December 1923 | Initiation of Watanabegumi | November 1951 | Establishment of Seiwa Civil Engineering Co., Ltd. with Capital of 1,250,000 yen at 1-4 Nihonbashi-Kabuto-cho, Chuo-ku, Tokyo |
| December 1938 | Establishment of Watanabegumi Co., Ltd. with capital of 180,000 yen | September 1972 | Renamed as SatoRoad Co., Ltd. Moved to Nihonbahi-Kotenma-cho 1-2, Chuo-ku, Tokyo |
| December 2001 | ISO 9002: 1994 | December 1998 | ISO 9001 |
| June 2003 | ISO 9001: 2000 | |
| WatanabeSato Co., Ltd. |
| October 2005 | Watanabegumi Co., Ltd. and SatoRoad Co., Ltd. merged to form the new WatanabeSato Co., Ltd. |
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