While developing countries continue to buy up feature phones, where prices continue to plummet, Japan's feature phones remain resistant to the smartphone substitution seen in western countries. Docomo has also started offering an unlimited voice call service -- a feature that's arguably more comfortable on longer-shaped feature phones and another reason for the carrier to continually refresh its gara-kei lineup.

Fujitsu's latest model, the F-07F, has a 13-megapixel camera, 1,000mAh battery and a 3.3-inch color display: specs that make it a high-end feature phone, but (camera aside) pale in comparison to cheap, entry-level smartphones like the Moto E. Here's one more surprising point: feature phones might cost less to make, but due to carriers subsidies for smartphones (in a bid to keep its customers upgrading), feature phones often cost more per month than mainstay Android devices from the likes of Samsung and Sony. There may have been a few smartphones in flip-phone clothing, but Japan's gara-kei aren't going anywhere soon.