"Conbini" is the Japanese word for convenience stores like Seven-Eleven. I counted 12 conbini in my neighborhood within a radius of 500 meters from the railway station. It is true that I live in a densely populated residential area of Tokyo, but 12 seems like a lot, especially since there are so many other retail outlets nearby-more than 100 small specialty shops on six or seven busy streets around the station, and three large supermarkets.

In 1927, a small store in Dallas, Texas, developed a new and convenient way to sell food products and everyday items. This, we are told, was the beginning of the convenience store. In Japan, the first convenience store is said to have opened in 1969, and the first American-style Seven-Eleven began operations in 1974. Since then, large supermarkets and corporations have invested in the conbini industry, one after the other. In the spring of 2001, Japanese franchise chains alone operated about 38,000 convenience stores, and annual revenues totaled more than 6.7 trillion yen.

This means that in Japan, on average, there is one convenience store for every 3,400 people, and per capita spending in them is more than 50,000 yen per year.

One reason for this phenomenal performance is the Point of Sales (POS) system. The system works like this. Computer networks link cash registers in stores to the franchise headquarters. The cash registers have push-keys to record customer gender and age group-for example, middle-aged man, student, or elderly lady. When a customer buys something, the clerk punches the relevant key. In this way, customer data is correlated with the product and price information obtained from the bar codes of the items purchased. Customer and sales data is transmitted from each store to headquarters, where it is stored and analyzed in real time. This makes it possible to: (1) fine-tune each store's delivery schedule; (2) identify with precision which products are selling well at a specific store, then adjust its inventory of about 3,000 commodities to concentrate on those products; and (3) develop new products that, hopefully, will sell well.

This results in stores that are more compact yet even more efficient than convenience stores in the United States. Japanese conbini go through a process of elimination until they are offering an excellent selection of products that are in demand locally, while using shelf space efficiently. They are small stores, but now play an important role in Japan's consumer society.

About 75% of the revenues of a conbini come from food products, and half of these are fast foods, side dishes, fresh confectionaries and the like, all delivered on a daily basis. Both fast food restaurants and conbini sell ready-to-eat food, but we don't eat in the convenience store, of course-we take the food home or to work, and eat it there.

Take-out meals called bento are packaged in small boxes. They typically contain rice and different servings of food. One popular "fast food" is O-nigiri, rice pressed into a ball the size of a fist, with fish, meat, pickles or other ingredients inside-a Japanese-style "sandwich." Since ancient times, O-nigiri have been a take-it-with-you lunch, and now convenience store chains are producing them in large quantities.

These take-out foods are popular as a simple lunch or supper. Two reasons why they sell so well: you don't have to bother cooking a meal, and they are cheap (300 to 500 yen). People living alone in the city are certainly glad to eat them, and this sentiment is growing among elderly people, who are living alone in increasing numbers. No wonder they choose the take-out way-it's a lot easier and cheaper to buy ready-to-eat food than to buy all of a meal's ingredients and cook for one person.

I think one reason that conbini are well patronized in shopping and residential districts is that we Japanese have never had the custom of stocking lots of food at home. We generally buy just enough food for one day at a time, except for items that keep well, like rice and seasonings. After all, the sea around our islands offers a daily supply of fresh fish, and farmers send vegetables and other produce to market on a regular basis. On outlying islands, people often shop every morning for food for breakfast, and in rural towns you might see a morning market. In the United States and other countries it is common to buy a week's supply of groceries at a large supermarket, but we Japanese wouldn't want to do that. Conbini sell fresh food for the home, and this has spurred their growth.

Attracting customers with fresh produce delivered several times a day has a down side-making so many small deliveries wastes energy. Another problem is the fatty, nutritionally unbalanced diet that results if we depend too much on ready-to-eat conbini meals. We cannot ignore the adverse health effect this can have, especially on the young.

One more challenge for conbini is to find ways to develop a more personal relationship with their customers, the type of relationship small "mom-and-pop" neighborhood stores cultivated to maintain a strong customer base.