ATOK is a family of Japanese input method system for Android, Windows, macOS, iOS developed by JustSystems, a software company with many years of experience. ATOK for Android is the most popular Japanese input keyboard of the paid apps, and embedded apps for smartphones, tablets, or car navigation systems. Android 2. 3 / 3. 0 / 3. 1 / 3. 2 / 4. 0 / 4. 1 / 4.