What is seibu kaihatsu?

As an AI language model, I don't have access to up-to-date information about companies. However, as per public information, Seibu Kaihatsu is a Japanese real estate development company that was founded in 1949. The company is headquartered in Tokyo and primarily focuses on the development of residential, commercial, and resort properties in Japan. Seibu Kaihatsu has also expanded its operations into international markets, particularly in Southeast Asia. Additionally, the company is also involved in the management of hotels and resorts, as well as the operation of golf courses.