Re: Ranking systems in different countries
Going back to the original question of whether one would have to retake the tests if he were to move from, for example, Indonesia to the United States...
For the kyu grades, I'm sure that it's at the discretion of the dojo whether or not to recognize the level one has obtained. Having some form of documentation will help, no doubt.
For example, in Spain, I was provided a booklet to document the tests I had passed and the seminars I had attended. Each test/level and seminar was signed and dated by the head Sensei in the booklet. When I moved to the U.S., I provided this documentation to the head Sensei at the new dojo. He was happy to acknowledge the level I'd attained.
And in his words, "When your skill reaches the next level, provided the time requirements have been met, you can test for the next level."
But again, deciding whether or not to recognize your kyu level is really going to be up to the Sensei at the new dojo.