He didn’t need to open it. He already knew what was inside: a receipt for ¥300,000, dated August 12, 1998. And a blank postcard.
The Unpaid Debt
Sensei paid back the missing money from his own pension. He gave Kenji a receipt for the amount, and a blank postcard. "When you can repay the debt," he said, "write the date and the amount on this card. Then send it. Not before." jlpt n1 old question
He addressed it to the old cram school’s address, knowing it would return as undeliverable. He sealed the envelope. Then he walked to the post office, bought a stamp, and dropped it into the red mailbox. He didn’t need to open it