Returning fire in an ongoing price war, DDI Corp. said Thursday that it will cut rates for some local calls by an average of 27 percent next month.

The reduction will take effect Oct. 1, when DDI merges with KDD Corp. and IDO Corp. to create a new entity nicknamed KDDI.

The lower rate will apply to city-to-city calls made within the same prefecture. For example, a daytime call over a distance of between 20 km and 30 km within a prefecture will cost 30 yen per minute, compared with 40 yen for 45 seconds. A night call of over 170 km within a prefecture will drop from 50 yen for 36 seconds to 20 yen for 90 seconds.

The move is intended to bring KDDI's local call rates closer to those offered by NTT East Corp. and NTT West Corp., the two regional units of the Nippon Telegraph and Telephone Corp. group, DDI President Yusai Okuyama said.

On Aug. 31, NTT East Corp. and NTT West Corp. announced they would reduce charges for certain calls within the same prefecture by an average of 40 percent, effective Oct. 1.

Major telecommunications firms have recently been cutting rates because customers will soon be able to select their telephone company in advance, starting in May. Many telecom firms believe this will make it more difficult to lure customers away from rival firms.