Hi Juji,

I thought I would add my 2 cents on this 
subject.  I almost always send my IPMO's to Japan 
with regular airmail.  It usually takes 4-5 days 
to get there.  I have sent well over 100 IPMO's 
with this method with *no* problems.

I have used Global Priority a few times and it 
seems like it gets there maybe 1 day sooner.  I 
used EMS only once because of a special 
situation.  That payment arrived in Japan the 
very next day, but the price - WOAH - a little 
too steep for just sending a payment, IMHO.

IMO, I would just send it by airmail and save the 
bucks.  But you should go with what makes you the 
most comfortable.  I can remember how nervous I 
was about doing everything correctly the first 
time I sent a payment to Japan, but it soon wears 
off.

Hope this helps in some way.
Luna-Art >^.^<