対戦 Hit Blow is a two-player puzzle game for Android that involves guessing each other's numbers. The first person to guess correctly wins the game. The game also has a single-player mode where you can play against the computer (which is relatively easy).

If you choose to play via Bluetooth, you will need to search for the other player's device. One player should select "find a new opponent," while the other player selects "be found by a new opponent." Once the pairing authentication is displayed, both players should accept it to start playing. For subsequent games, you can select the opponent from the list of available devices.

To play online, you will need a 4G connection (Wi-Fi is not supported). You will need to register as a user the first time you play (no specific fields are required). For subsequent games, you can use the same user ID.

If you change your smartphone, you can display your user ID from the menu on your old device and enter it on the user registration screen on your new device.