King Sinmu of Silla (Hangul/Hanja: 신무왕/神武王; Reigned. 839, died 839), whose born as Kim Woo-jing (김우징/金祐徵) was the 45th monarch of the Korean kingdom of Silla. His reign was the shortest in the state's history, lasting only from the fourth to the seventh lunar month of 839.
King Sinmu was the son of the Sangdaedeung Kim Gyunjeong (?–836), a descendant of King Wonseong (r. 785-798) and cousin to King Heungdeok (r. 826–838). Upon the death of King Heungdeok in 836 a succession struggle erupted between Kim Gyunjeong and his nephew, Kim Jeryung (?–838). Woo-jing and his follower, Kim Yang supported Gyunjeong, while Kim Myeong and Kim Rihong stood by Jeryung. Jeryung's party ultimately triumphed and Gyunjeong was killed. Kim Jeryung was then crowned as King Huigang in 836.
Yang escaped, but Woo-jing did not. Though being pardoned promptly by the new king, he soon became threatened by Myeong who became Sangdaedeung. So in 837, Woo-jing fled and entrusted himself with Jang Bogo in Cheonghaejin Military Quarters, Wando County, Southern Jeolla Province. However, a year later, Myeong fomented a revolt against King Huigang which killed several of the King's aides. Faced with defeat, King Huigang committed suicide. Kim Myeong then ascended the throne as King Minae.
Kim Yang, who was then concealing himself on a mountain near the capital, heard the news and raised up an army to go to Cheonghaejin. He told Ujing of these events and persuaded him to have his revenge. Woo-jing asked Jang Bogo to help him to take advantage of the confusion of the country and to make himself a king. Jang Bogo agreed and had his friend Jeong Nyeon also follow Woo-jing. In 839, Woo-jing and his followers defeated King Minae's army at the battle of Dalgubeol (Daegu) and quickly advanced upon the capital. All the king's aides then ran away leaving the king behind, so the king hid himself in a villa near the royal palace. Soldiers came into the palace and searched for the king. Finally, they found the king in the villa and killed him in spite of his pleas. Kim Rihong was also killed. Woo-jing then placed himself on the throne as King Sinmu.
He died three months later from disease and was buried on Mount Jehyeong in the Silla capital of Gyeongju (Specific Location: 11 Hugogan Drive/Hugogan-gil, Dongbang-dong 669-beonji). It is also said that Sinmu dreamed of seeing the dead Rihong shooting an arrow into him. Sinmu awoke with a start when the arrow hit him, but the wound remained real, becoming worse and worse, finally leading to his death.