本稿では、甲斐における政治的拠点が、武田氏の本拠地であった躑躅ケ崎館を中心とする古府から、甲府城とその城下町へと移行する過程を、徳川家康の領国支配のあり方と連動させながら検討した。その際、甲府城築城の開始時期をめぐって、これまで天正11（1583）年、天正13年、天正17年とする三つの説があったのに対し、天正13年と推定されることを論証し、武田氏滅亡後、家康による領国支配の拠点となる甲府城の築城が早期に計画されたにもかかわらず、完成が文禄─慶長期に至った事情を次のように考察した。すなわち、家康の甲斐入国から天正12年尾張出陣以前に、一条小山への甲府城普請の沙汰がなされていたが、普請の開始命令は、長久手の戦い後、天正13年１月であった。さらに、真田氏攻略や、一条小山とその周囲に所在した一蓮寺等の寺社や湯田の集落の移転に手間取り、天正17年伊奈熊蔵の検地によりその替え地が確定された。しかし、天正18年の家康の関東移封を迎え、甲府城普請は頓挫した。結局、築城事業を動かしたのは加藤光泰であり、城下町移転とともに事業を完成させたのは浅野長政・幸長父子であった。
This article examines the relocation of Kōfu’s administrative headquarters from Tsutsujigasaki Manor House, which served as the Takeda Clan’s base of operation, to Kōfu Castle and the surrounding castle town, while analyzing the character of domainal rule under Tokugawa Ieyasu. Currently, there is no scholarly consensus about the year in which Kōfu Castle’s construction began. Scholars have offered three dates: Tenshō 11 (1583), Tenshō 13, and Tenshō 17. This article argues that construction was most likely initiated in Tenshō 13. Although Tokugawa Ieyasu planned to begin the construction of Kōfu Castle soon after the Takeda Clan’s defeat, it was only in the Keichō period that the Castle was finally completed. While a plan for the construction of Kōfu Castle in Ichijō-koyama appeared sometime between Ieyasu’s arrival in Kai Province and the conquest of Owari Province in Tenshō 12, the command to commence construction was not issued until the first month of Tenshō 13 after the Battle of Nagakute. Moreover, disruptions related to the Sanada invasion and efforts to relocate villages in the Yuda area and Buddhist temples in and around Ichijō-koyama, such as Ichirenji, delayed construction, and it was not until Ina Kumazō’s Tenshō 17 cadastral survey that a relocation site was finally designated. However, the project once again stalled as a result of Ieyasu‘s move to the Kanto region in Tenshō 18. Ultimately, it was Katō Mitsuyasu who helped restart the project and was the father-son duo of Asano Nagamasa Yoshinaga who, together with the relocation of the castle town, helped to complete it.