Japanese automakers' U.S. sales slid mostly sideways last year, but their China business is booming. Two manufacturers, Mazda Motor Corp. and Mitsubishi Motors Corp., finally are selling more vehicles in the world’s biggest market than in the United States. Last year, Mazda’s passenger vehicle sales in China grew 8.3 percent to 309,407 vehicles, while its U.S. sales slid 2.8 percent. Mitsubishi’s sales in China also eclipsed those in the U.S., growing 56 percent to 129,

In a study done by J.D. Power’s Chinese division, recent months have shown that the Chinese have improved both the technology behind their cars as well as the engineering. Improvements have been made to raise their domestically produced automobiles to international standards primarily in the internal systems of the cars; the engine, transmission, ventilation and the heating and cooling. The study looked at 213 car models sold by 65 different car brands while surveying around