Great Internet service is not difficult to find here in Japan as this country is known for its hyper-sonic, yet stable Internet infrastructure. What can sometimes be an intimidating task for foreigners is the language skills necessary to complete the sign-up procedures and/or obtain customer support.
Enter Asahi Net. They're an English-speaking Japanese ISP, making it easier to sign-up and obtain support in good ol' English. Their English website, refreshed with a modern look and clear descriptions, does a bang-up job of explaining the various options and offerings.
I myself have been an Asahi Net customer for quite a number of years now, and I've had a more than satisfying customer experience with them. If my memory serves me correctly, my service only went down once during my entire history with them. The cause was a faulty modem, which was promptly replaced by NTT. My service even survived the 2011 earthquake without much more than a brief hiccup. Coolest for me is that they also offer an optional static IP address, making IT guy me the envy of my IT guy cronies.
Even more awesome is that as an Asahi Net customer myself, I can offer my readers deep sign-up discounts. Simply provide my Asahi Net user ID when you sign-up --> sb8d-pvln
More info on the discounts here: http://asahi-net.jp/en/service/campaign/syokai.html
Best of luck to you, fellow foreigner!