NTT Docomo Inc. unveiled 10 new smartphones Thursday to beef up its non-iPhone lineup for the winter-spring season and improve its competitiveness in a tight market.

Given that rivals KDDI Corp. and Softbank Corp. only launched six and four new smartphones, respectively, powered by Google's Android operating system last week, Docomo's 10 new handsets suggest it is trying attract customers with variety.

"I think having variety in your lineup is essential," said Docomo President Kaoru Kato during the unveiling event in Tokyo.

The 10 new smartphones are all powered by Android, and Docomo plans to push three of them with strong ad campaigns and discounts — the Aquos Phone Zeta by Sharp Corp., the Arrows NX by Fujitsu Ltd. and the Xperia Z1f from Sony Corp.

Last month, market leader Docomo finally gave in by deciding to sell the latest models of Apple's iconic smartphone, the iPhone 5s and 5c, to halt the erosion of its customer base. But in what may be a case of too little, too late, Docomo lost 66,800 net customers that month, its worst net loss ever, while Softbank gained 270,700 customers and KDDI added 232,700.

Kato remained optimistic, blaming the drop on lack of customer awareness and its own inexperience with the popular iPhone.

"It's still too soon to judge whether we are falling behind the competition," he said.

Kato said Docomo hasn't been able to keep up with demand and didn't even have enough handsets to distribute to all of its 2,400 shops.

Its other new smartphone units include Sony's flagship Xperia Z1, which has a 5-inch screen and state-of-the-art camera technology, and Samsung Electronics Co.'s Galaxy J, which Docomo asked Samsung to design specifically for Japan's market.