According to North Korean missile flies over Japan, the Japanese government sends emergency alerts to mobile phones if there's a suspected nuclear attack. How can I receive such notifications while I'm in Japan?
I'm renting a SIM card (data only, but that should be sufficient to get text messages, or notifications via the internet), and a fairly modern iPhone. Ideally I'd like to get warnings in English so I know what kind of disaster it's notifying me of, in case it's warning me of something else like a tsunami.
The Wikipedia article J-Alert states that most warnings (severe weather warnings aren't) are given in Japanese, English, Mandarin, Korean, and Portuguese. However, I haven't seen any examples of J-alert text messages being given in English.