The Richardson incident
Our story takes place in the domain of the Satsuma clan, whose capital was Kagoshima, but whose wealth came from the port of Yokohama, the main port in Japan for trading with the outside world. There were many foreign traders there, living in an area called the "Kannai", which was protected, an quarantined, by a moat. Foreign trade had made Satsuma the 2nd richest clan in Japan, but it also caused tensions.
On September 14th 1862, four British subjects were on an afternoon jaunt to visit the Kawasaki temple in present day Kawasaki. Two Yokohama based merchants, Woodthorpe Charles Clark and William Marshall, a Mrs. Margaret Watson Borradaile, and a Shanghai merchant, Charles Lennox Richardson. They had set out from Yokohama by boat that afternoon, picked up horses on the far shore, and were now riding through the vallage of Namamugi. Coming in the opposite direction was the large retinue of Shimazu Hisamitsu, taking up most of the road. Shimazu was the father of the Daimyo, or Lord, of Satsuma, but in reality he was the ruler as Regent, and he was travelling with his samurai escort. Now it was the custom for riders to dismount in the presence of important figures, and in fact samurai had the legal right to strike anyone they considered showing "disrespect". That these were hated foreigners only inflamed the situation more.
As the party squeezed past some of the samurai lashed out with their swords - the Britons fled, but were blooded and Richardson fell from his horse, mortally wounded. Hisamitsu gave the order for todome, the coup de grace.
A Japanese depiction of the event. Richardson is in the middle, in black with a top hat
There had already been several attacks on foreigners, but this was the last straw. The Satsuma authorities claimed they had only acted perfectly legally, but actually this was untrue as British nationals were exempt from the "disrespect" rules under the Anglo Japanese Friendship Treaty. What is possible is that Richardson, after 9 years in Shanghai, regarded himself as an Eastern expert, and maybe didn't realise that what would pass in China would not in Japan. Anyway, there were repercussions.
The foreign trader community in Yokohama clamoured for some sort of protection from their governments. The British Chargé d'Affaires, Lieutenant-Colonel Neale, demanded from the central government an apology for this and other incidents, such as the murder of 2 sailors from HMS Renard in June. Neale also demanded a huge indemnity of £100,000, rather bizarrely in Mexican silver dollars, about 1/3 of the total revenues for one year. He got it too, but demands to the Satsuma government for reparations, the surrender of those responsible, and guarantees for the future, were ignored. Losing patience a British squadron was sent to Kagoshima, the Satsuma capital, in a show of force.