Though Japan is famous for importing technology from the West and then sending it back in cheaper and better form, business practices remain homegrown. The shining exception is convenience stores, an American concept that has been so successful here that one could say it subsidized the rest of the Japanese retail industry during the recession of the '90s.
The reasons for this success are still being debated, but most theories have to do with the increased urbanization of the Japanese landscape and the attendant splintering of family life into ever smaller household units. On a more calculable level, convenience stores provide the kinds of things marketing people drool over: high merchandise turnover; a young and discriminating clientele; and, thanks to the POS system, instant feedback in the form of sales results reported on an hourly basis.
Convenience store marketing is as close to an exact science as retail gets. Food companies, in particular, spend billions of yen developing products that specifically appeal to konbini users. The stores have limited shelf space and too many manufacturers vying for that space, so if an item doesn't "perform" it is immediately dumped.