was one of the sons of Japanese Emperor Go-Daigo

Emperor Go-Daigo

Emperor Go-Daigo was the 96th emperor of Japan, according to the traditional order of succession....

. He became involved in the Nanboku-chō wars

Nanboku-cho

The , spanning from 1336 to 1392, was a period that occurred during the formative years of the Muromachi bakufu of Japan's history.During this period, there existed a Northern Imperial Court, established by Ashikaga Takauji in Kyoto, and a Southern Imperial Court, established by Emperor Go-Daigo in...

 between the true Imperial line and the Ashikaga clan

Ashikaga shogunate

The , also known as the , was a Japanese feudal military regime, ruled by the shoguns of the Ashikaga clan.This period is also known as the Muromachi period and gets its name from Muromachi Street of Kyoto where the third shogun Ashikaga Yoshimitsu established his residence...

.

In 1336, Tsunenaga was sent along with his brother Takanaga

Prince Takanaga

was the second son of Emperor Go-Daigo of Japan, and fought for his father in the Nanboku-chō Wars. Since the characters used to write "Takanaga" can also be read as "Takayoshi", the prince is sometimes known by that name as well....

 to be escorted by Nitta Yoshiaki

Nitta Yoshiaki

' , son of Nitta Yoshisada, fought for Emperor Go-Daigo, against the Ashikaga at the end of the Kamakura period. He was one of the chief generals at the fortress of Kanagasaki, which fell to the Ashikaga; Yoshiaki was killed, and Prince Tsunenaga captured....

 to Echizen Province

Echizen Province

was an old province of Japan, which is today the northern part of Fukui Prefecture. It was sometimes called , with Etchū and Echigo Provinces.Echizen is famous for washi . A text dated AD 774 mentions the washi made in this area. Echizen-produced Washi is still the most commonly sold traditional...

 where, it was hoped, they could escape the attacks of the Ashikaga. According to the epic Taiheiki

Taiheiki

The is a Japanese historical epic , written in the late 14th century. It deals primarily with the Nanboku-chō, the period of war between the Northern Court of Ashikaga Takauji in Kyoto, and the Southern Court of Emperor Go-Daigo in Yoshino....

, Tsunenaga was secretly made heir-apparent before he left, but no other documents confirm this. In fact, in November of that year, his brother Narinaga

Prince Narinaga

reigned from 1334 to 1338 and was one of two Seii Taishogun during the Kemmu Restoration. He was also Crown Prince in 1336 ....

 was officially named Crown Prince.

Fleeing the Ashikaga, Nitta brought the Princes away from Yoshino, where the Southern Court of Go-Daigo was based, towards Tsuruga

Tsuruga, Fukui

is a city located in southern Fukui Prefecture, Japan.-Outline:One of city of Wakasa Area, present southern Fukui Prececture. Municipalized on April 1, 1937....

 in Echizen. They faced a terrible defeat in the Battle of Minatogawa

Battle of Minatogawa

The Battle of Minatogawa also known as the Battle of Minato River was fought in 1336 between Japanese forces loyal to Emperor Go-Daigo and the Ashikaga clan. The Imperial forces were led by Kusunoki Masashige and Nitta Yoshisada, while the Ashikaga were led by Ashikaga Takauji. The Ashikaga were...

, but survived and eventually made it to the castle of Kanagasaki

Siege of Kanagasaki (1337)

The 1337 was the final battle for the Nitta family in their support of the Southern Imperial Court against the Ashikaga Pretenders of the Northern Court....

. In January 1337 the castle came under siege, and by April those inside were reduced to eating horseflesh to survive, and almost resorted to cannibalism before surrendering. Tsunenaga escaped from the castle, but was captured and killed soon afterwards.