Kōfu (甲府市, Kōfu-shi, Japanese: [ko̞ːɸɯᵝ]) is the capital city of Yamanashi Prefecture, Japan.

Kōfu has a humid subtropical climate (Cfa), though it is less wet than either the south or Sea of Japan coast due to its location in a shielded mountain valley.

During the Heian period, a branch of the Minamoto clan, the "Kai-Genji" ruled over vast shōen estates, and developed a military force noted for its use of cavalry.

By the Muromachi period, a branch of the Kai-Genji, the Takeda clan came to dominate the area, and built a castle in what is now part of Kōfu.

During the Edo period, Kai Province was tenryō territory ruled directly by the Tokugawa shogunate, and Kōfu Castle remained its administrative center.

Following the Meiji restoration, with the establishment of the modern municipalities system, the town of Kōfu was proclaimed on July 1, 1889.

The city experienced a major flood disaster in 1907 (明治40年の大水害) caused by heavy rain in a typhoon from the night of August 21, 1907 and by deforestation which was accelerated in Yamanashi Prefecture, due to the need for wood for fuel of the steam engines of the growing industrial policy of the Fujimura Prefectural Government.

Patrol diaries of Masaki Tsukasa Kasaburo said "This heavy rainfall causes rivers to run down, landslides and levee failures, bridge piers destruction, etc., resulting in the destruction of homes and villages, village isolation, runoff, and traffic disruptions caused serious damage[5] 233 people died, 5757 houses were run out, 650 hectares of lands have been buried or run down, 3353 landslides, collapse and damage distance of about 140 kilometers of levees, runoff and burial of roads, the damage distance was about 500 kilometers, 393 telephone poles collapsed.

[8] Kōfu has a mayor-council form of government with a directly elected mayor and a unicameral city legislature of 32 members.