Gearing up for a price war in the country's fixed-line phone market, KDDI Corp. and Japan Telecom Co. both said Wednesday they would introduce a basic monthly fee cheaper than that of industry behemoth NTT Corp., along with a single long-distance rate.

Japan Telecom, recently acquired by Softbank Corp., which is headed by billionaire entrepreneur Masayoshi Son, had unveiled a discount service only last month.

Just a few hours after KDDI announced its new rates Wednesday, Japan Telecom announced further rate cuts so that it could continue to claim to be the cheapest carrier -- by a razor thin margin.