Nearly every home, guesthouse, and Airbnb in Korea uses a 도어락, a keypad lock instead of a physical key. Hosts text or KakaoTalk the code ahead of your arrival instead of meeting you in person. To open it: tap the keypad to wake it up, type the 비밀번호, then press 별표. That last step catches people off guard. Most Korean digital locks confirm the code with that star key, though a handful use # instead. If the door doesn't respond, just try the other one.