3:00 p.m. sharp, every afternoon, a small boy appeared at the sandbox in the park across from the apartment complex. His name was Yuto, a kindergartener. With his favorite blue shovel in hand, he faced the sand with the utmost seriousness.
Another child would always show up soon after.
A girl with long, fluffy hair tied back, dressed in a red dress. Her name was Mina. She went to the same kindergarten as Yuto, though they were in different classes.
It all began when Mina praised the sandcastle Yuto had built alone.
“That’s so cute! I bet if we made one together, we could build something even cooler!”
Her sparkling eyes made Yuto blush a little, but he nodded.
From then on, every day at 3:00 p.m., they would meet and build sandcastles together. They shaped towers with buckets, used twigs as flags, and lined paths with stones. Even naming the castle was a serious matter in their tiny kingdom.
“Today’s castle is Princess Donut Castle!”
“Then I’m the king!”
“Whaaat? Then I’ll be the dragon!”
Their playful banter echoed through the sunlit park. They even had “rules”: always destroy the castle before leaving, never show anyone the secret “jewel,” and always finish building together.
It was their little pact—their form of friendship.
But one day, 3:00 came and went, and Mina didn’t show up.
Yuto sat alone in the sandbox, gripping his shovel. The hands of the clock moved, shadows stretched across the park—but there was no sign of her.
“She probably just had something to do today.”
He told himself that. And he came back the next day. And the day after that.
But Mina never returned.
One week later, Yuto made a decision.
“I have to build our final castle.”
He had to follow the rules. That, he believed, was his promise to Mina.
That day, he came to the park with a bigger bucket and colorful stones. He carefully shaped the sand, built tall towers, double walls—his most magnificent castle yet.
Older kids passed by and laughed.
“Still playing in the sandbox?”
But Yuto didn’t care. This was an important promise.
When the castle was finished, he dug a small hole at its center. From his pocket, he pulled out a marble—blue, the one Mina had once called “a jewel” on the day they first met.
He buried it in the heart of the castle and gently pressed his palms together.
“Mina… thank you for coming.”
Just then, a breeze blew through the park, and one of the castle’s towers gently crumbled. It felt, somehow, like someone unseen was saying “thank you” back.
After that, Yuto stopped visiting the sandbox.
But the “Sandcastle Promise” stayed with him. Meeting someone special. Building something together. And knowing how to end it properly.
Years passed. Yuto grew up.
One day, he happened to pass by that same sandbox. There, a group of children were busily building a castle, their faces full of joy.
Yuto smiled.
“A new story is beginning again.”
