I wish I had seen this a week ago, before I returned from Tokyo. The 1000 yen issue was a real PITA, especially since we learned it the hard way by tying up a machine for a few minutes in a futile attempt to get rid of all of our coins. This was the first time we actually realized that converting to Suica currency was a great way to get rid of coins, which we usually just took home with us, and we had a bag full at the time.
On a mostly unrelated note, I managed to mix in some 100 won S. Korean coins in with my huge cache of Japanese coins from my many previous trips. When trying to pay for a drink at DisneySea, the poor clerk had to inform us that this is not Japanese money,
. I felt like a total idiot, but the two coins are very similar in size and appearance, aside from the obvious fact that the tiny script is in hangul instead of kanji, and the image is a man wearing very Korean-looking hanbok. I haven't even been to Korea in a while, so I was surprised I had so many coins from there.