Self-checkout @ Japan

In a land where service is king, a few big retailers are committing lèse-majesté. They are replacing checkout clerks with machines.Japan's biggest retail group by revenue, Aeon Co. , has put nearly 3,000 automatic checkers in hundreds of stores nationwide. Wal-Mart Stores Inc. 's Japan subsidiary plans to more than double the number in its stores in 2015.

To economists, the trend is heartening. Investment in labor-saving devices could boost long-term growth and help corporations overcome a shortage of workers willing to do menial jobs at low pay. American retailers long ago realized this and stuffed their stores with automatic checkers-to the point that Wal-Mart's U.S. unit has begun restoring more human checkers to deal with problems machines can't answer.