With the latest Apple iPhone model hitting Japanese stores on Friday, the nation's three major carriers are wracking their brains over how to get a lead in the market despite a plethora of similar products.

NTT Docomo Inc., KDDI Corp. and Softbank Corp. will have a hard time differentiating themselves because they offer the same iPhones, similar prices and pay plans, but also have service, speed and coverage that are comparable for most users.

Some analysts said the competition is likely to come down to cash-back incentives to defecting subscribers.