I’m trying to plot how get the Ryukyu Kingdom to become a British protected state similar to the Kingdom of Tonga and the most likely point of divergence so far appears to be the Bombardment of Kagoshima and its aftermath. The general idea is that due to [REASONS] – more forces, better planning, simple luck etc. – the British are more successful and in the negotiations are able to force the Satsuma to declare invalid their previous claims over the Ryukyu Kingdom. This is followed up by a speedy diplomatic agreement with Sho Tai for the kingdom to become a protected state. That still leaves China however as the kingdom was a tributary of the Qing until 1874 so I need to find a way to get them to recognise both Ryukyu’s independence and their agreement with Britain. The best I can find so far is the Chefoo Convention thirteen years later, so was wondering if anyone knew of any diplomatic agreements in the intervening period which could be used instead? Thanks.