Tsutsujigasaki Castle was the fortified residence of the final three generations of the Takeda clan, located in the center of the city of Kōfu, Yamanashi Prefecture, Japan. It is not a Japanese castle in the proper sense of the word, and is not referred to as a "castle" in Japanese, as it was famously the policy of the Takeda clan to "make men your castle, men your walls, men your moats". Nevertheless, it is listed as one of Japan's Top 100 Castles. The ruins have been protected as a National Historic Site since 1938. The site is open to the public and now contains the Takeda Shrine, a Shinto shrine dedicated to the deified spirits of the Takeda clan.

Kōfu is the capital city of Yamanashi Prefecture, Japan. As of 1 April 2019, the city had an estimated population of 187,985 in 90,924 households, and a population density of 880 persons per km2. The total area of the city is 212.41 square kilometres (82.01 sq mi).