In recent years, Korean firms have registered a large number of patents in the United States. As noted by the Chosun Ilbo IBM registered the most patents in the U.S. last year with 5,896, and Samsung Electronics rose to No. 2 with 4,551 and LG Electronics ranked ninth with 1,490 patents. Judging by the number of registered patents, Korea is a major force, but the atmosphere is quite different on the frontlines, where Apple, Microsoft, Philips and other global IT companies have launched a patent war against their Korean rivals. They have started using patent and copyright law to protect their smartphone and LED technologies and to pressure Korean IT firms. The main battleground in the patent wars is the smartphone market.As the Chosun Ilbo points out, U.S. companies virtually control the global market for operating systems, which determine the success or failure of a smartphone. Korean companies have plenty of patents for manufacturing technology, but very few for software.