TOKYO (Reuters) - NTT DoCoMo Inc <9437.T>, Japan's biggest mobile phone carrier, filed for an injunction to halt sale of a handset using No. 3 Softbank Corp's <9984.T> network, marking the latest move in a bitter fight for market share.
DoCoMo, which is struggling to win new subscribers, said on Monday that a Softbank handset made by Toshiba Corp <6502.T> released in March was "extremely similar" in design to a DoCoMo handset made by Fujitsu Ltd <6702.T> and first sold in 2006.
The two handsets, which both target older people with easy-to-read menus and simplified design, have similar keypads, menus and color schemes, DoCoMo and Fujitsu spokesmen said.
A Toshiba spokeswoman said she could not comment until the firm had received a copy of the complaint. Softbank spokesmen said they were still collecting information.
Softbank, which bought Vodafone's
It has since forced its bigger rivals, which together hold about 80 percent of Japan's 100 million mobile phone users on their books, to match its prices.
Prior to the announcement, shares of DoCoMo closed down 3.3 percent at 149,000 yen, while Softbank ended down 5.6 percent. Fujitsu closed down 4.7 percent while Toshiba shed 3.8 percent.
(Reporting by Mayumi Negishi and Taiga Uranaka; Editing by Gary Crosse)