Pop into any electronics store in Japan and you will see two types of mobile phones. The more common variety is a smartphone, exemplified by Apple Inc.’s iPhone. The second type of handset is often called “gala-kei”--a shortened word that combines the words “Galapagos” and “keitai,” the colloquialism for a mobile phone in Japanese.

Also known as feature phones in the rest of the world, Japan’s “gala-kei” handsets earned that monicker because they have evolved in isolation from the rest of the world, adapting to the local environment...