カギを開ける

It is an application to open the key to dial expression in the round-robin.
The number of digits Yes prepared from one digit to five digits, the next digit has become to be unlocked and opened the previous digit.
This app does not mean there is a hint as escape game, you must Ika try the set of all numbers on your own.
It is recommended when the head such as is vaguely immediately after wake up in the morning.