If you want an extremely entry level look into life at Japan, this parody rap video done to the tune of “Nothin’ But A G Thang” will tell you all you need to know about convenience stores and blood type obsession. Of course, you have to endure parody rap (the lowest of low), so I’d really just recommend Wikipedia.
Never has the “pointless video tag” seen better use.
[youtube=http://www.youtube.com/watch?v=EnTYoXtifcA&color1=0xb1b1b1&color2=0xcfcfcf&hl=en&feature=player_embedded&fs=1]