Shot at East Park in Imperial Palace, Tokyo.
The Imperial Palace is surrounded by moats because it was a seat of the Tokugawa Shogunate. And every moat has it's own name. The water in this photo is 'Inui Moat'. Inui is a direction and means northwest. The moat is located in the northwest of the main tower of the castle.
Before the castle was built, this moat was a natural river. And the tall stone wall was built along the valley. Time passed and the moat became a place for relief. Two boats are riding on the moat silently.