The pictures on the screen of the two huge high-definition TV sets in a Tokyo hotel ballroom last week were crystal clear. The colors were vivid. The resolution was so fine that the image of the five executives cutting a ceremonial ribbon looked almost three dimensional. The occasion: the expansion of Japan's HDTV broadcasting to eight hours a day, up from the one-hour tests begun in 1989. With its sharpness of picture and CD-like crispness of sound, Japan's HDTV has all the outward appearances of another grand success about to wash over the world.
Yet despite the lifelike clarity achieved after...