Somewhere 10

優先席
ゆうせんせき
Priority seating

This sign is meant to allow old, pregnant or injured people to get a seat on the train. However, there are some Japanese rules of etiquette which can circumvent this rule. The only way to be rude in Japan is if you know you are rude. If you bump into someone but keep walking, that's fine, you didn't realise you'd bumped into them. If you walk past a coworker on the street on a Saturday morning and not say hello, it's okay as long as you look as if you hadn't noticed them. And lastly, if you pretend to be in a deep sleep while sitting in the priority seats, there's no need to stand up no matter how old or pregnant the person who needs it looks.

Now if the needy person is a bit adventurous, they may say すみません or something, and force the salaryman or teenager to notice them. Then they will immediately jump out of the priority seat and apologise as if they'd only that moment realised someone needed the seat. Hardly anyone will ever move of their own accord.