Sonno Joi (尊王攘夷)

Sonno Joi is a philosophy of respect for the Emperor and rejection of external pressures and foreign enemies. In Japan, it was discussed passionately among people from Chotei Court officials to the general public at the end of the Edo period and became a watchword for the anti-establishment movement.

Summary
The phase was coined from Sonno as the base of the country and Joi to stand against foreign invaders. It means 'Son 尊(respect) O 王 (Emperor) jo 攘(expel) i 夷 (foreigners)'. In the Chunqiu period in China, the leader used the slogan meaning 'To respect (尊) the Emperor (王) and protect Zhou Dynasty, we have to expel the iteki (夷狄 [unfamiliar tribes, at that time the Chu Dynasty to the south of Zhou Dynasty]),' and scholars of Japanese classic literature imported to use it. Lord Huan of Qi (a state in Zhou Dynasty) held other lords together to subdue iteki including Chu without being disrespectful to the Zhou court. It was the scholars of Sung-period Neo-Cunfucianism who raised a loud voice about Sonno Joi after that.
While the Chinese character '王' was used in '尊王' (Sonno) in China because 'O' (王) was modeled after the Emperor of the Zhou, Sonno was also written as '尊皇' because '王' had meant the 'Emperor' (皇) in Japan who was not just a King but someone more revered since Sonnoron (Imperialism) was accepted in Japan

Sonnoron (Imperialism)

In Japan, Sonnoron is a philosophy that, based on the concept of Japan as the nation defined in the "Kojiki" (The Records of Ancient Matters) and the "Nihonshoki" (Chronicles of Japan), claims that Japan exists because of the will of the Emperor (God). The idea that the cultures, ethnic groups and nations originate in God is universal and developed differently, such as a theory of the divine right of kings in which the authority of kings is thought to be granted by God. It is also the same all over the world that the idea that the ethnic groups and nations originate in God becomes radical as a nation and its people are in crisis.

Joiron (principle of excluding foreigners)

In Japan, during the peaceful Edo period which had lasted more than 200 years, people never thought that they would go abroad to get something or that foreigners might ever come to Japan to steal something from them. However, European countries which started to explore the world after the Age of Geographical Discovery to expand their areas of dominance and the USA which rode on the wave of continuous Imperialism and made a foray into Africa and Asia for incursions and colonization became a threat for East Asian countries.

When Admiral Perry of the the East India Squadron visited Japan, this Kyoka (comic Tanka) was created: 'Jokisen woke me up from a long peaceful sleep, only four of them but kept me awake all night.'
<Jokisen> was also a name of Gyokuro green tea. This Tanka was cynical about the confusion by a double meaning of 'four cups of Jokisen tea kept us awake all night' and 'four Jokisen (steamboats) created chaos in the whole country which kept us from sleeping all night'.

As Qing Dynasty went into the Opium War with England in southern China and lost Hong Kong, Japan began to face growing tension after the incidents such as the Golovnin Affair in Hokkaido and the Phaeton Incident in Kyushu. Although, to deal with the situation, they could either accept foreign visitors by 'Kaikoku' (opening the country to the world) and go overseas themselves, or expel the visitors to keep the (previous) peace, 'Joi' was the idea and concept of the latter. Within Japan, it was a time that ethnic consciousness was rising rapidly together with the spread of Kokugaku (study of Japanese literature and culture). While the whole situation was very complex, the major trend at the end of the Edo period was that the Tokugawa Shogunate and the Satsuma Domain who insisted on opening Japan to the world were at odds with the Choshu Domain who insisted on expelling foreigners. Additionally, under pressure from some European countries and America, the Emperor agreed to the Treaty of Amity and Commerce in 1865, which made it impossible for 'Sonno' and 'Joi' to be joined together. Some samurai such as Takamasa OKUNI of Tsuwano Domain supported the principle of Daijoiron, which was the concept that, to resist pressure from the allied western powers, it would be best to temporarily open the country to the world and give priority to uniting the whole country and fukoku kyohei (strengthening the military). This created the possibility for the conflicting principles of opening the country and expelling foreigners to converge toward the goal of attacking the shogunate. Then later, with the intercession and help of Rhoma SAKAMOTO of Tosa Domain, two large local forces of Satsuma and Choshu Domains turned toward attacking the shogunate at the end of the Edo period.