Since we here in Japan are in the future it will already be Monday when Super Bowl XLIIIJKLMNOPQR comes around. For those football fans in Japan who will be lucky enough to be home at that time (coverage starts at 8:10 AM JST) NHK BS-1 will be the only ones airing the whole shebang live. http://www.nhk.or.jp/sports/
You can also catch the replay at 18:15 on NHK BS-1 or for those of you who don't have BS-tuners you'll have to wait until 24:29 on N-TV. In both cases, the game will be clipped so no Bruce Springsteen for you latecomers. The game will also be rebroadcast several times throughout the week on either N-TV G+ (whatever that is) or GAORA. http://www.nfljapan.com/schedule/
If you're working and are at a computer, perhaps TVAnts, TVU or Livestation will have the game somewhere. I don't know if the Livestation BBC channels will have the game (it's on BBC-1) so your best bet might be using TVAnts or TVU to find the CCTV Sports feed from China.
Another option if all you want are the scores is using your keitai to access NFL Network Mobile. However, you have to pay 315 yen per month if you want to "continuously seeing" the site. I have no idea what is and isn't pay access only. You can use the QR-Code from the site link and the mobile site is in English and Japanese. If you don't want to do that, ESPN mobile actually works fairly well on most phone browsers. http://www.nfljapan.com/mobile/index.html