The boy nodded at the jōnin with the same innocent smile then turned back to his food.
Katsu slurped his dish, eating like a pig. He finished it quickly and let out his breath in satisfaction. The boy looked down at his dish and smiled. He called over the owner of the shop, waving.
"Thanks for the dinner, sir," he said. "How much is it?"
"16 Ryō," the old man answered. Katsu pulled out a couple of coins, counting the money, putting the coins down on the counter one by one. 
"10... 11... 12..."
His face turned bright red when the coins in his hand were all on the counter. "I... Er..." He searched himself, trying to find something. After a few moments, he gave up and looked down in defeat. "I seem to be short a couple of coins... Is there anything I can do to make up for the money?"
The old man gave Katsu a skeptical look. He ran his hand through the coins, counting them. Pausing for a moment, he looked up to the boy again. "Bring the money next time you're here," the man warned him and swiped the coins off the table.
Katsu smiled widely and nodded. "Right! Sorry," he said cheerfully and walked out, waving back. He walked on the streets, his eyes glowing bright red, scanning the area.