E-commerce giant Rakuten Inc.'s mobile unit started taking limited orders for services on its network Tuesday after a delay in installing network base stations forced it to postpone a full-scale launch until next April.

Rakuten Mobile Inc. initially aimed to make a full-service entry into Japan's mobile phone market Tuesday, bringing it into direct competition with the nation's three established telecommunications companies and spurring greater competition in the saturated market.

It will kick off the new network by offering free services to 5,000 people in Tokyo's 23 wards, Kobe, Nagoya and Osaka.