Originally Posted by
Aussie2B
The only thing preventing Japanese carts from playing in a US N64 are the presence of plastic tabs in the corners of the cartridge slot. If you remove those, you can pop a Japanese game right in. You can cut them out, which is tricky and generally involves taking the system apart, or if you don't care about it being real pretty, you could melt them down with a soldering iron like I did. I'm sure you can do a search on the forum or Google and find more details about the various methods people have used.
There are plenty of notable Japan-exclusive N64 games, but they just don't get any attention because the fan base for N64 importing is basically nonexistent. You should do a search for N64 import recommendations since I know there have been several topics on the subject in which I've posted lots of recommendations with descriptions.