Currently sitting on the Yokohama line to Hachioji, a little before Hashimoto station. Looking at the map the train had already reached Hashimoto. Seems like we're running 30 seconds or maybe 1 minute late.
Is it possible the map is a little in the future for every train, to make sure you arrive on time when using it?
Even a 3 second delay is unacceptable in JP ;)
I had a train arrive two minutes late over the weekend in Osaka and I could see people visibly agitated and worried when looking down the platform.
The hype about "on time all the time" is a well-loved-by-foreign-media myth in Japan. Yes, many trains are nearly perfect (Shinkansen, especially), but plenty of Tokyo metro lines are delayed by a few minutes during the daily rush hour crush. The point: They run so many damn trains, you can just get on another one.
Because commuters often have tight connections to make and if a train is two minutes late that can be enough to miss the next train and be late to work, which is a big no-no.
Out of curiosity I checked few cameras and it looks like you're right.