(1359âÂÂ1398) was a Nanboku-chà  period warrior and the Kamakura-fu's second Kantà  kubà Â, or Shà Âgun Deputy. Son of first Kantà  Kubà  Ashikaga Motouji, he succeeded his father in 1367 at the age of nine when this last suddenly died during an epidemic. It was during his reign that the Kanto kubà  title became common enough to appear for the first time in writing. It is in fact contained in a 1382 entry of the . This title was in itself rebellious, because it was first adopted by Takauji himself and its use therefore implied equality with the shogun. In fact, sometimes the Kanto Kubà  was called Kantà  shà Âgun.
Ujimitsu was the first Kantà  kubà  to openly aspire to the shogunate, and his relationship with shà Âgun Ashikaga Yoshimitsu in Kyoto consequently deteriorated to the point of being likened to that of "cats and dogs".
Ujimitsu became Kantà  Kubà  at the age of nine when his father suddenly died at the age of 29 during an epidemic. Because of his extremely young age, he was given Uesugi Noriaki as a regent and Rinzai Zen priest Gidà  Shà «shin as a tutor. (Noriaki however died the following year and was replaced by his son Yoshinori.) Immediately after Ujimitsu's accession to power, Uesugi Noriaki left Kamakura for Kyoto to represent the Kantà  kubà  at Ashikaga Yoshimitsu's accession ceremony. Taking advantage of his absence, some Musashi families, led by the Kawagoe and the Takasaka clans, revolted against Ashikaga rule in the so-called , and were soon joined by Shimotsuke Province's Utsunomiya clan. The Uesugi however remained faithful and defeated the coalition.
Ujimitsu worked continuously to define and solidify the structures of the Kamakura Bakufu he had inherited. Having gained full control of Kantà Â, he then conceived the idea of becoming shà Âgun, taking advantage of the fact that shà Âgun Yoshimitsu was busy subduing Kyà «shà «. He however over the years abandoned the idea after Uesugi Noriharu committed seppuku in protest and he came to realize his lack of reliable support from other clans like the Toki and the Kyà Âgoku. He ordered a campaign against Oyama Yoshimasa, a Kantà  supporter of the Southern Court against the Ashikaga, who had revolted. Although Yoshimasa was defeated and killed in 1382, the fight against the Oyama clan continued for Ujimitsu's entire life. In 1391 he allied himself with shà Âgun Yoshimitsu against the Yamana clan and, although the campaign ended before he could participate, he was nonetheless rewarded with the Mutsu and Dewa Provinces.
Ujimitsu never completely abandoned the ambition to become shà Âgun, and gradually his relationship with shogun Yoshimitsu worsened to the point of being described as one of open enmity. The fact he didn't have to suffer the consequences of the situation is probably due to the good offices of his childhood tutor Gidà  Shà «shin who, being in Kyoto, could intercede for him with Yoshimitsu, but also to the mediation of the Uesugi and to his work against the Oyama clan, which had served the interests of the Ashikaga's Kansai branch.
He died at the age of 41 and was buried at a Rinzai temple near Kamakura called , later incorporated in Zuisen-ji). This is the same temple where in his grandson Mochiuji, defeated in 1439 by Kyoto's army, would commit seppuku disembowel himself to avoid the shame of capture.
On the spot near Zuisen-ji where YÃ Âan-ji used to be stands a stele, which reads:
<blockquote> When Kantà  kubà  Ashikaga Ujimitsu died on January 11, 1398, he was given the posthumous name . His son Mitsukane built this temple and gave it his father's posthumous name. The temple's oshà  Dombo Ushà «à  was a follower of Musà  Soseki. On March 24, 1439 kubà  Mochiuji, a descendant of Ujimitsu, fought here against shà Âgun Yoshinori, was defeated and disemboweled himself. The temple was burned and never rebuilt. This is where it stood.<br /> Erected by the Kamakuramachi Seinendan in March 1926 </blockquote>