The Greater East Asia Treaty Organisation (GEATO) is an organisation set up by the Empire of Gensokyo after Second World War. Its members include Kanako's India, China, Satori's Republic of Cambodia, Byakuren's Republic of Thailand, Utsuho's Korea and of course, Gensokyo themselves.
The Solvent Union tried to join the organisation in 1959, but was rejected because they were redheads that nails down a garden all day. Kogasanian Britain tried to join the organisation in 1967 because they still held on to Hong Kong, but was rejected because the Secretary General of the Greater East Asia Treaty Organisation at the time got a heart attack and died when they saw Kogasa Tatara, apparently the Secretary General was so surprised/scared to death by her appearance. However, Kogasanian Britain was later accepted in 1983 by a Secretary General who always expect the unexpected.
After the real Nitori Kawashiro became President of Russia, she requested to join the Organisation, in which the Secretary General immediately accepted.