Add connection card
接続カードを追加する
既存の分野で追加の調査を行った場合はいつでも追加のカードによって追記できる（追記もIDによって判別）
Zettelkasten rules
When you discover connections between cards that may seem unrelated at first glance, you can create a Connection Card, a special card whose purpose is to explain the relationship between the links between the cards.