The Order of the Garter was started as a joke and continues as such : why was the Japanese Emperor ordained?

Question

And why the ostrich feathers - to make it even funnier?

Answer 1

To entice stupid,culturaly retarded americans over to spend their money here.

The Japanese Emperor was invested (not ordained) with the order because,at the time,he was an ally of Britain and,with the advent of the second world war,was stripped of the title.He asked to be allowed to wear it on his last trip to Britain but,his request was refused.

Answer 2

It was started in 1348 and the way it was started is not fully known so it is impossible to know exactly why it was started. It is quite common for foreign Monarchs to be invested with the honour and currently seven foreign monarchs are "Stranger" Knights and Ladies including as you correctly said Emperor Akihito of Japan. his father Hirohito was also honoured in this way, the honour was removed from him in 1941 during World War II but it was restored to him in 1971.