How did you do that? I was just thinking about what I should do to be reachable by phone while in Japan, since I'm going to get murdered by roaming rates on my crappy Argentine SIM. I had considered stuff such as buying Skype credit and using wi-fi hotspots to do my calls, but I guess getting a SIM I could use on my phone to be more easily reachable would we way better than that.
http://www.jqphone.com/e_japansimcards.html
Same one my teacher uses, and she heads back to see her family every year.
A few important notes:
1. You need an unlocked phone
2. Select the right type of SIM card for your phone
3. This only works in Japan
4. Rates are 85 cents per minute local or international, 12 cents per text from within Japan to someone else in Japan. Texting to someone outside of Japan? Prepare to bleed out of your ass ($1.40 per text). All incoming texts or calls are free.
5. Don't ever use data with this SIM. It's crazy expensive (29 cents per 10Kb!) Stick to wifi, pocket wifi, a data card...anything but this.
6. You'll have to submit ID and credit card info before they activate it.
7. After 5 years it costs 8$ a year. Until that point, nothing more than the onetime cost and whatever you end up using in Japan
In short: great, cheap, easy way to text/be reached in Japan even if you/the person you're texting may not have access online.
Use it in any other way at your own discretion.