Do people also call each other during a letter date?

Maezawa from the President’s Office here as well. In “letter dating,” “letter” refers to written communication, including LINE. Basically, it means communicating by text. If you mean that the other person called you after you exchanged LINE contact information, the arrangement is considered complete once you’ve exchanged your first messages. From there, you’re free to pursue a personal relationship, so whether you meet or talk on the phone is fine as long as you both agree. If you don’t want to talk on the phone, just let the other person know. Even if you decline to pursue a personal relationship—including saying that you don’t want phone calls—the club won’t get angry with you. A personal relationship is just that: personal.