A group of 49 Japanese magicians is suing two local television networks for revealing the secrets behind a series of coin tricks in news footage.
The case, filed in Tokyo District Court on Tuesday, seeks damages of 1.9m yen (£8,239) from Nippon Television Network Corp and TV Asahi Corp.
Magician Shintaro Fujiyama said the broadcasters had "deprived professional magicians of their assets".
Asahi said it saw no problem with the footage. Nippon TV declined to comment.
"It takes us many years to develop a coin trick as a professional tool," said Mr Fujiyama, 52.
"They must understand how all the time we have spent is wasted by exposure of the trick," he said.
The two networks revealed how the coin tricks were completed last November, after a magician and a pub operator were arrested for punching holes in coins.
It is against the law to damage or melt coins in Japan.