How did Confucianism influence ancient Japanese government?

During the Tang Dynasty in China (619-907 CE), the Chinese were focused on growing their empire by creating tributary states. Regions like Korea, Japan, and Vietnam were subjected to Tang traders and armies as the Tang sought territorial expansion. Korea adopted many Chinese-style reforms, like education systems, writing, and Confucianism, while Vietnam adopted far less Chinese elements, particularly in southern Vietnam.
Japan, on the other hand, was distinctly influenced by Tang China and more specifically Chinese Confucianism. During the Taika Reforms of 645, land, power, and education systems were modeled after Confucian China. The greatest change was in power structure; the position of an Emperor was imported from Confucian China to Japan in an attempt to unify warring regions within Japan. Japanese students were sent to China to learn about Chinese writing, literature, and religion, all based on Confucius' teachings.
The Taika Reforms, however, did not have the intended effect on Japan. While the position of Emperor was technically around until the dissolution of the Japanese Empire after World War II, the Emperor had no actual power in Japan. Instead, power resided in the Shogun, supported by daimyos who served as both lords and greater samurai. The Emperor only gained nominal power once the American Admiral Matthew Perry forced Japan to open its borders to trade in 1853.