Simplify the following text for a Grade 6 native English-speaking person.
Original: This island , which was formed by digging a canal through a small peninsula , remained as the single place of direct trade and exchange between Japan and the outside world during the Edo period .
Simplified: The island was made by digging a canal through a small peninsula . It was the only place of direct contact and trade between Japan and the outside world during the Edo period .