Softbank Corp. said Monday it will start offering a discount land-line telephone service beginning in December, a move expected to deal yet another blow to industry behemoth NTT Corp.

The service will be offered via Japan Telecom Co., a land-line operator bought by Softbank from U.S. investment fund Ripplewood Holdings LLC earlier this year.

For the first year of subscription, users will be able to make free unlimited calls to three numbers registered in advance. They will also benefit from 90 percent discounts on any other long-distance calls during certain hours.