KDDI Corp. said Monday it will begin selling four new smartphones this summer, including the HTC J One, the Japanese version of an internationally renowned model by Taiwanese maker HTC Corp. featuring enhanced sound.

Buyers who sign a two-year contract can get the HTC J One, which comes with stereo speakers next to its screen, for about ¥35,000 in early June, said KDDI, which runs the au brand.

The other models are Sony Corp.'s Experia UL, featuring a large, high-resolution screen, Kyocera Corp.'s Urbano model, and Sharp Corp.'s Aquos Phone Serie, which can be used for about three days when fully charged thanks to its energy-efficient Igzo screen.

All four models run Google Inc.'s Android operating system.

NTT DoCoMo Inc. is set to launch 10 new models.

KDDI will also start in June a phone service that customers can call around-the-clock for advice and instructions about how to use their smartphone. To get access, customers must register for the service, pay an initial charge of ¥3,150 and a monthly fee of ¥399 from the fourth month after signing up.