Asia, Air Law and Medical.
Medicals in China and Japan are very tough, especially on BMI.
With the Americans I flew 'N' tails (in Australia and Asia) on a 'Validation' which was simply filling out a form. The FAA licence itself requires an exam. There is a booklet with hundreds of questions and requires rote learning, an oral exam and flight test.
The JAR licence is a problem and requires doing their ATPL exams, flight test, Instrument rating, the whole nine yards.
There use to be some relief if you had time on type above a certain weight, I think 40 tons by memory. I'm sure someone here will know. Best to contact the appropriate authority.
When we all fly in each others airspace on a daily basis it seems an 'International' licence would make sense but that would cause job losses with the 'biro munchers'.