[6] In this campaign, Dōsetsu fought against the Ōuchi clan in Umegatake castle [jp], Buzen Province, where he emerged victorious despite being outnumbered by around 3,000 men.

[a][17] In 1554, Dōsetsu was dispatched to suppress several rebellions that broke out in Bungo and Higo provinces, which were incited by Obara Akimoto, Honjo Shinzaemon, and Nakamura Shinbei.

Following that, Dōsetsu sent letters commending his vassals for their outstanding performances during this operation, such as Korenobu Yufu, Takano Daizen, Adachi Sakyō, and Ando Iesada.

[26][27] For his achievements in pacifying the Ōtomo-clan enemies, Dōsetsu was appointed by Sōrin as Kabanshu (personal assistant) and Shugodai (governor) of Chikugo province.

[28] In 1561, during the siege of Moji Castle which was controlled by the Mōri clan, Portuguese merchants assisted Dōsetsu with three ships weighted between 500-600 tons.

[30][31] On July 13, Dōsetsu and his subordinate Korenobu Yufu[21] defeated the Mōri clan army in the battle of Yanagigaura in Buzen Province.

[38] However, this truce did not last long, as on 25 March, in The Fourth Battle of Yanagigaura, Dōsetsu once again fought the Mōri clan army, which was led by Koremaki Yufu.

Dōsetsu had already anticipated this movement and fielded a rearguard of 3,000 soldiers with the assistance of his lieutenants, Bekki Shigetsura, Ono Shizuyuki, and Korenobu Yufu, with each of them leading 500 to 600 cavalry.

To resist this newly arrived enemy, Dōsetsu, Usuki Akisumi, and Yoshihiro Akimasa engaged the Mōri clan forces at the foot of Mount Tachibana.

[b] On November 25, Dōsetsu entered Chikugo Akashi Castle and married Hitoshihime, the daughter of Monchūsho Akitoyo, an Otomo vassal.

[58] Later the same year, Dōsetsu personally led the Otomo forces against the Mōri clan in the Tatara area (located in modern day Higashi-ku, Fukuoka), where they engaged in at least four battles which ended in deadlocks.

[59] On 18 May, after several engagements at the Battle of Tatarahama, the Ōtomo army, led by Dōsetsu, Usuki Akisumi, and Yoshihiro Akimasa, clashed with 40,000 soldiers under Kikkawa Motoharu and Kobayakawa Takakage.

[38] At this point, the Mōri clan suddenly lost their motivation to defend Tachibana Castle from Dōsetsu, as their own territories were threatened by Yamanaka Yukimori and Ōuchi Teruhiro.

[67] However, this campaign, which ended on 20 August, was considered a catastrophic defeat to Ōtomo forces, due to the massive casualties they suffered and failure to complete their objectives.

[23]: 358  Dōsetsu also resigned from the position of Karō (senior official) of the Ōtomo clan, and assumed a more active role in the military command of Chikuzen Province.

[80] As the Ōtomo clan indeed suffered massive defections from their vassals due to their loss in Mimigawa, Dōsetsu stayed loyal.

[92] On 18 April, Dōsetsu rescued an Ōtomo-clan general named Shiga Chikamori, from being pursued by Akizuki Tanezane, by tricking the latter with some deceptions.

[96] From 18 August until early September, Dōsetsu engaged in three separate battles against the armies of Harada Nobutane, Munakata Ujisada, and the Sugi clan in Tatarahama, Hakozaki, and near Agematsu Castle, respectively.

First, Dōsetsu fought Tanezane and Ujisada in the Battle of Koganebara,[116] which was recorded as the largest military engagement in Kurate District, Fukuoka, up to that time.

[121][122] Contemporary Italian Jesuit Alessandro Valignano recorded that Muneshige was adopted by Dōsetsu and inherited the headship of the Tachibana clan.

300 of Muneshige's troops launched a surprise attack from the side with guns, while the remaining 200 soldiers were led by Komono Masutoki, who set up a false flag to make it look like reinforcements from the Ōtomo clan were coming, and finally managed to lift the siege.

Muneshige then led 1,000 cavalry including Komono Masutoki, Korenobu Yufu, and Shigeyuki Ono, and eliminated 300 of the Harada general's troops.

[165] Furthermore, after burning down several settlements within Akizuki Clan's territory around Amagi and Amamizu, Dōsetsu and Shigetane proceeded to capture many castles in Mizuma District.

This alliance involved many Ōtomo enemies such as Kusano Chin'ei, Nabeshima Naoshige, Tsukushi Hirokado, Ki Shigefusa (also known as Utsunomiya Chinfusa), Nagano Sukemori, and Goto Ienobu.

When, in 1578, Ōtomo Sorin planned to subjugate the Shimazu clan in southern Kyushu, Dōsetsu firmly opposed this policy.

[186] Dōsetsu was said to possess a "strength that above any ordinary men" and mastered a particular sword style that was named tachiuchi ni myō o etaru (the art of slashing in all directions).

[187] According to the chronicle of Bekkidōsetsu Jō-jō Bekki gundan, Dōsetsu managed to personally kill three Mōri clan generals, namely Motonori Akagawa, Motochika Katsura, and Motoyo Reisen, during the Battle of Yanagigaura on 13 October 1562.

Meanwhile, other records, from Bekki Gundan and Kyūshū shoshō gunki, have stated that in 1567 Dōsetsu personally killed two enemy warriors, namely Katsura Motochika and Akagawa Motonori.

[197] As a military commander, Dōsetsu participated in melee combats during his wars, despite suffering from paralysis in his left leg due to an accident at a point during his life, which forced him to ride in a carriage carried by his followers, even during battles.

To reference the story of Dōsetsu, a major character named Kakashi Hatake uses one of these techniques to cut a bolt of lightning in half.