1590: On the Eve of Unification
The western provinces, Kinai, and central Japan were already under Toyotomi control, and all major lords nationwide were in a state of submission. The Odawara Campaign destroyed the Hojo in Kanto, and the Pacification of Oshu brought the Tohoku lords into submission, eliminating remaining independent forces. The last obstacles to national unification were removed.
Events this year
3/29
The Toyotomi army attacked Yamanaka Castle, a Later Hōjō stronghold guarding the route to Odawara, and captured it within half a day.
See this battle in detail →Sources 三島市「山中城跡（国指定文化財「史跡」）」／三島市「戦国・安土桃山時代」／静岡県「しずおか文化財ナビ 山中城跡」
4/3
Toyotomi Hideyoshi arrived at Odawara and his assembled armies began the siege of the Later Hōjō stronghold.
See this battle in detail →Sources 小田原市「小田原合戦」／小田原市「石垣山一夜城」／小田原市「史跡・石垣山」
6/14
After being besieged for about a month by Maeda Toshiie and Uesugi Kagekatsu under the Toyotomi, Hachigata Castle surrendered. The loss of this stronghold ended Hōjō Ujikuni's control over northern Kantō.
Sources 寄居町「鉢形城跡」
6/23
Toyotomi's northern army under commanders including Maeda Toshiie and Uesugi Kagekatsu attacked Hachiōji Castle and captured it in one day.
Autumn
In connection with relocation to Kantō, Tadakatsu was given command of Ōtaki in Kazusa Province with 100,000 koku and became its lord, remaining in residence for approximately eleven years until 1601.
Sources 千葉県立中央博物館「当館について」（大多喜城分館）
7/5
Hōjö Ujinao, who had held out in Odawara Castle, surrendered to Toyotomi Hideyoshi, ending the Odawara campaign.
8/1
After being transferred to the Kantō region, Tokugawa Ieyasu entered Edo Castle and made Edo the center of his domain.
Month 11
Former retainers in the confiscated Kasai and Osaki territories rose against the newly installed Kimura house before being defeated at Sanuma Castle.
See this battle in detail →Sources 仙台市博物館「伊達政宗に関する資料（2）」／登米市「首壇」／文化遺産オンライン「伊達政宗書状」
Toyotomi Hideyoshi entered Aizu and settled the territories of the northern daimyō. Date Masamune lost Aizu, which was granted to Gamō Ujisato.
The Hōjō built approximately 9 kilometers of defensive palisades surrounding Odawara's castle town. This integrated military fortification with the residence of samurai, townspeople, merchants, and temples, creating a unified fortified urban center.
Sources 小田原市文化財保存活用地域計画
In connection with Toyotomi Hideyoshi's settlement of Kantō and Ōu, Ishikawa Kazumasa entered Matsumoto and undertook renovation of the castle fortifications and development of the castle town. There are theories that his domain was valued at either 80,000 or 100,000 koku.
Sources 松本城管理事務所「松本城の歴史」
At Hideyoshi's insistence, Date Masamune participated in the Odawara campaign and submitted to Hideyoshi's authority. During the Ōshū Settlement, his Aizu domain was confiscated.
Sources 仙台市博物館「主な収蔵品11 伊達政宗に関する資料（2）」