物理キーボード配列変更 (+親指Ctrl) [日本語配列] is a free Android application developed by ShiftRot, falling under the Utilities & Tools category. This app is specifically designed for Japanese users who are facing difficulty in typing Japanese characters on aJapanese hardware keyboard connected to their Android device via Bluetooth, as it is treated as an English layout by default. With this app, users can choose from different Japanese layout options, including a standard Japanese layout and a layout with [Convert] / [No conversion] replaced with [Ctrl] to use [Ctrl] key with thumb. Additionally, users can also switch between [Half/Full] and [ESC], [Caps] → [Half/Full] with ease.

It is important to note that this app cannot change the keyboard layout, and the basic layout remains an English layout. The Japanese keyboard layout is released as a separate app. Please note that the app's functionality may be limited on devices that do not allow the "Keyboard layout selection" option under "Settings" → "Language & input" → "Physical keyboard." This limitation is due to the device manufacturer and not the application itself.