(FORTUNE Magazine) – Once renowned as the masters of imitation, Japanese manufacturers of consumer electronics are learning how it feels to fight a war against copycats. A 1992 survey by the Ministry of International Trade and Industry shows the number of illegally copied product lines more than doubled over 12 months, to 154 (see chart). The counterfeiters: unidentified companies in China, Hong Kong, South Korea, Taiwan, and Thailand. They sell a broad range of fakes both domestically and as exports, mainly to other Asian countries, but also to Europe and the U.S. Matsushita Electric complains that its National brand is showing up on electric irons made in Thailand and on videotapes made in China. Hitachi sees the counterfeiters moving up the technological ladder from televisions to semiconductor chips. As their own victims once discovered, the Japanese are finding it hard to stop foreign fakers. They rely partly on government-to-government protest, which proved futile when the boot was on the other foot. Consumer tip: Watch for misspellings. Counterfeiters mistakenly believe this absolves them of trademark infringements. You can often tell a Sony from a phony, for example, by products marked ''Sonny'' or ''Soni.''

CHART: NOT AVAILABLE CREDIT: FORTUNE CHART/SOURCE: MITI CAPTION: FAKES