[Frost1x]

Not sure about biggest but I will say NY subway is far more complex than Tokyo's and I'm a native English speaker and speak no Japanese.

Getting to the correct train in Tokyo was far easier, likely because there was less rerouting than what seems like perpetual issues in NY's subway due to aging infrastructure.

[remarkEon]

I’d echo this sentiment. I’ve spent a good amount of time in Tokyo (I don’t speak Japanese either, beyond simple “I am lost” and “where is the toilet” phrases), and for whatever reason I do find Tokyo’s trains easier to handle than New York’s. I can get around New York on my own without a map but that’s just because of brute force memorization and getting off at the wrong stop enough times.

[IshKebab]

Also NY's is the only system I've seen that has fast and slow trains on the same line. Definitely complicates things!